PURPOSE: To obtain a weighing device which provides rapid and accurate calibration through simple operation, by applying different calibration via cams successively.

CONSTITUTION: When synchronous motor 56 is rotated once while the load of a body to be measured carried by a conveyor is not applied via sliding pin 8, balance rail 21, etc., cams 70W72 rotate interlocking to oscillate levers 44W46. Consequently, loads corresponding to calibration weights 50W52 are applied to main body 22 of the balance via reception plates 30, 42, and 43 and to load cell 35 successively and processing the output of cell 35 in the minimum squaring method, etc., determines the regression straight line formula of the loads and electric signal output corresponding to the secular change of cell 35, etc., so that the rapid and accurate calibration is automatically performed through simple operation.