It is a calibration device for a measurement instrument (101) for measuring a compressive force or a tensile force in a longitudinal direction exerted to a linear body (11) from a predetermined correlation. A stopper part (104) for fixing the linear body (11) is fixed at a one end side entrance (3) and a push/pull movable part (105) for enabling the linear body (11) to be pushed and pulled in an insertion/withdrawal direction at an other end entrance (4) is fixed, so that the relative positions of the stopper part and the push/pull movable part with respect to a sensor main body (2) cannot be changed. A force detector (109) measures the force in the insertion/withdrawal direction exerted from the push/pull movable part (105) to the linear body (11). The force detector (109) is interposed between the push/pull movable part (105) and the linear body (11).