Many urbanized cities in Japan are located in alluvial plains, and the vulnerability of urbanized areas to flood disaster is highlighted by flood attacks due to heavy rain fall or typhoons. Underground spaces located in the urbanized area are flood-prone areas, and the intrusion of flood watar into underground space inflicted severe damages on urban functions and infrastructures. In a similar way, low-lying areas like "bowl-shaped" depression and underpasses under highway and railroad bridges are also prone to floods. The underpasses are common sites of accidents of submerged vehicles, and severe damage including human damage occasionally occurs under flooding conditions. To reduce the damage due to inundation in underground space, needless to say, early evacuation is one of the most important countermeasures.
 This paper shows some experimental results of evacuation tests from underground spaces under inundated situations. The difficulities of the evacuation from underground space has been investigated by using real scale models (door, staircase and vehicle), and the limit for safety evacuation is discussed.
 From the results, it is found that water depth of 0.3 - 0.4m would be a critical situation for the evacuation from underground space through staircases and door and that 0.7 - 0.8m deep on the ground would be also a critical situation for safety evacuation though the doors of the vehicle.
 These criteria have some possibility to vary according to different inundated situations, and they are also influenced by the individual variation like the difference of physical strength. This means that these criteria requires cautious stance to use although they show a sort of an index of the limitation for saftty evacuation from underground space.

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 The present research investigates issues concerning space underground and concerns itself with psychological evaluations of comfort in underground railway premises from the perspective of the users of such premises. The actual psychological evaluation was done on the premises of nine Nagoya City underground stations. Four factors were extracted from the results obtained.
 The first factor is transmission information, the second factor is the comfort of the environment, the third is sense of insecurity, and the fourth, convenience.
 A covariance structure analysis was carried out to see if there was any relationship between these factors and the research participants' age and frequency of underground usage. It was found from this that the first element is related to the frequency with which the participants in the research use the underground trains. When the frequency of use is high, transmission of information is high. A relationship was also found between aging and factors one and four. The older the person the worse information transmission is and the more dependent they are on convenience, such as, for example, in terms of elevators and escalators.

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 Improvement of infrastructures in Japan is now shifting its pivoting foot from the age of construction and increasing to the age of maintenance. After the importance of maintenance was pointed out, a lot of studies about engineering techniques concerning to the maintenance has been carried out at various organizations and authorities.However, their effort is not enough till now for the establishment of rational maintenance techniques, especially in the underground structures. On the other hand, against the background of the realization for safer and more secured society, the use of an underground space is more and more expected. So the development of the maintenance and management technique in the underground structure becomes more and more important, indispensable problem. Here, the technique to evaluate the performance and the deterioration characteristic of the underground structure were examined from the viewpoint of the asset management, aiming at contributing to the establishment of the maintenance and management technique of the underground structure.

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 In many big cities there are some shopping centers located under the roads. Most of those underground shopping centers were constructed in 1955-1975. Therefore the earthquake-proof renewal of them is the important issue now. This paper shows the present situation on the earthquake-proof construction of the underground shopping centers in Japan and indicates how to check the earthquake-proof function and endorsement it. This study was conducted by the investigation committee in the Institute of Future Urban Development and the author was the chair of that committee.

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