PURPOSE: To enable the execution of the calibration for a pertinent area simply by setting a calibration factor corresponding to the acceleration of gravity in a zone to be used.

CONSTITUTION: The weight of an object to be measured is detected with a load cell 1 and the detection signal is introduced into a sensitivity adjusting circuit 3. The load detection signal from the circuit 3 is fed to a gravity acceleration correcting circuit 4 and taken out as mass signal calibrated according to zones via variable resistors VR1WVR16 on which resistance values are set corresponding to values of gravity acceleration in sixteen zones based on the measurement law and a switch S and then, introduced into a data processing section 6 via an A/D converter 5. The processing section 6 determines weighed values by executing arithmetic processings such as tare offsetting and charge conversion and feeds the results to a display 7.