It is need to maintain the durability of concrete structure from the viewpoint of the proper control of maintenance. The ultrasonic method which is one of nondestructive tests is utilized as the degradation evaluation of concrete structure. When the ultrasonic method is applied to an inhomogeneous material, the ultrasonic wave intricately passes around the degraded parts of the material. Though the intricate change of the wave is considered to depend on the types of degradation, there are few researches surveying the relationship between the change of the wave and the types of degradation. Thus, in this study, numerical analyses are conducted with considering various types of degradation so as to discuss their influence to the wave propagation of an ultrasonic wave. It is clarified that the wave change is correlated to the types of degradation.