Tensile strength of concrete is directly related to the strength of the shear cracking, which influences the stiffness degradation of the RC member. Furthermore, the tensile strength affects the pull-out strength of the post installed anchor bolts in the retrofitting process. The tensile strength is estimated by the equation with the compressive strength. However, the previous study on the tensile strength of concrete of the existing buildings is not sufficient, therefore it is not clear that the current equations are applicable to those concrete. As such, the splitting test was conducted using a test specimen obtained from the same RC member, from which the test specimen for the compressive test was obtained. Splitting tensie tests were conducted with core cylinder. Variation of tensile strength obtained from the splitting test without supporting strips is considered. However, those strips in the splitting tests are not required in Japanese Industrial Standard, considering that the tensile strength from the splitting test without bearing strips is lower than the theoretical value.