The entrances and exits of pit dwellings are the ways in and out of the family space while also acting as ways in and out of the social space that is the settlement.　But although they are important to the research of Jomon Period settlements, there is uncertainty about the direction of the entrances and exits of pit dwellings and the factors that determined them.
In this study, we looked the fire courts of 697 pit dwellings in 145 ruins in the Iwate Prefecture region, measured the orientation of the openings, and clarified the direction of the entrances and exits of pit dwellings.
We carried out comparative analysis of the direction of pit dwelling entrances and exits for each river system and recently （1977～2006） observed AMeDAS station data of the prevailing wind direction for summer and winter.
As a result, we recognized a tendency to orient openings from the east to the south in a southwest direction, taking into account the position of the valley and to avoid the prevailing wind of winter, which is heavily influenced by snowstorms.
In relation to topography, it is plausible that the direction of entrances and exits point towards the valley side to prevent influx of rain water into the pit dwellings.
In relation to climate, it is plausible that the direction of entrances and exits was selected to ensure sunlight in the pit dwellings as well as to avoid the effects of blizzards in winter.

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