To prevent the reduction in calibration precision of a force gauge by an earthquake, disturbance or the like in a force calibrating apparatus.

This force calibrating apparatus performs the calibration of the force gauge 1 by working the load of weights 3a etc., to the force gauge 1. This apparatus comprises a long-period seismograph 20 capable of measuring a long-period quake and a control unit (maintenance mechanism) 30 capable of interrupting the calibration of the force gauge 1 on the basis of the measurement value by the long-period seismograph 20.