To provide a weight loading method for suppressing variation in the height level of the center of gravity of a truck for a collision test due to loading of weight and change of the weight value.

In this weight loading method of the truck for the collision test that has a frame, mounts a body to be tested on the frame, and is accelerated by a pushing force and tractive force to a force added point of the frame, the frame includes a weight attaching opening allowing vertical insertion of a body of a first weight and an attaching seat for attaching the weight. The body of the first weight is inserted into the weight attaching opening and the flange part is attached to the attaching seat so that the center of gravity thereof is positioned under the attaching seat. The second weight is loaded in the upper part of the first weight so that the center of gravity thereof is positioned above the attaching seat.