To provide a device for measuring the axial force of a screwed body that can measure axial force while internal and external threads are actually screwed each other.

This measuring device is used to measure clamping force when an external thread Y and an internal thread X that are arranged opposingly are screwed relatively by at least two arrangement means that retain the external thread Y or the internal thread X at one end and are fixed to a body A that is essentially the same. The measuring device is provided with a seat surface torque load cell 2 having a top plate 1 where the seat surface of the external thread Y touches and a fixation part for fixing to the side of a body A, an internal thread torque load cell 4 for gear-locking the rotary direction of the internal thread X that is screwed to the external thread Y of the sear surface torque load cell 2, an axial load cell 3 for converting distortion being generated by the clamping of the external thread Y or the internal thread X being arranged opposingly, and a conversion part B for performing the conversion processing of the distortion that is obtained by the axial force load cell 3 as the axial force of the screwed body.