In this study, for the purpose of improvement of estimation accuracy for compressive strength of concrete by ultrasonic method, a measurement method for ultrasonic velocity and a strength estimation method for concrete were investigated. In the experiment with reinforced concrete members of actual size, the precision of proposed method for measuring ultrasonic velocity of inner concrete was confirmed to be high. Further, the estimated value of compressive strength of concrete in structure by proposed strength estimation method was close to the actual measurement value.
