To provide a male screw member which realizes an appropriate fastening by measuring the axial force of the male screw member such as a bolt by ultrasonic wave.

The squareness of the end surfaces of both the end parts of the male screw member to the shaft straight line of the male screw member is set to 0.0005-0.1 mm. Regarding the actual angle θ of the end surfaces of both the end parts of the male screw member to a virtual plane perpendicular to the axis which is perpendicular to the axis of the male screw member, tan θis set to 0.02 or below. The flatness of the end surfaces of both the end part of the male screw member can be set to 0.0005-0.1 mm, and the ten-point average roughness Rz of the end surfaces of both the end parts can be set to 1-15.