PURPOSE: To weigh a weight of a load on a platform at an arbitrary place and also make the platform movable.

CONSTITUTION: A jack 3 which can support a movable platform 2 in contact with the ground is provided at an appropriate position of the platform 2, and a load detector 4 is provided for detecting a load applied to the jack 3 while the platform 2 is being supported by the jack 3. Further a calculator 5 for calculating a load applied to the jack 3 based on a load detection value detected by the load detector 4 and a display device 6 for displaying the value calculated by the calculator 5 are provided. Thus the load W on the platform 2 can be weighed at an arbitrary place and the platform 2 is made movable by a self- traveling type vehicle 1A (1B, 1C), thereby eliminating a space which is always occupied for weighing.