PURPOSE: To measure the weight and the three-dimensional position of the center of gravity of a large structure in the measuring attitude of one configuration by measuring the reactions at three points in the reference attitude of a material to be measured and the increment of the reaction when the material to be measured is slightly inclined.

CONSTITUTION: The position of the reference attitude for measuring center of gravity of the material 6 is determined by the using a hydraulic actuator 3. Thereafter, the reactions at the reaction points are measured with load meters 1 and 2 at three positions. The weight is obtained as the total value. The position of the center of gravity (a) within an x-y plane is obtained based on the balance of moment around the orthogonally intersecting two axes. Then, the material to be measured 6 is slightly inclined with the actuator 3. The amount of movement from the reference attitude is measured with a potentimeter 4, and the increment of the reaction is measured with the backward-reaction measuring load meter 2. The position Z of the center of gravity in the direction of the axis (x) from rotary axes (a) and (b) is computed based on these values, the weight which is measured before hand and a distance L between the forward and backward load meters. In this way, the reaction are measured in, only one plane. Therefore, the measuring attituce can be matched to the operating state of the material to be measured.