This paper describes the chemical deterioration of concrete by soaking up of boric acid solution. The results of the examination are shown as follows. (1) The Effect of concrete leaching which may occur by boric acid solution soaking into concrete on concrete erosion and mass change is small. (2) The influence of boric acid solution soaking into concrete on compressive strength and static elastic modulus of concrete is not notable. (3) The area of the chemical deterioration of concrete by boric acid solution soaking into concrete depends on the concentration of the boric acid solution and the soaking period. A higher concentration and a longer soaking period make the deterioration area larger.