To allow easy alignment against the carriage rail and smooth relay between carrying trucks without drastically increasing the weight.

This rail truck is provided with a frame 1, a connecting rail 13 attached to the frame 1, a diaphragm that floats the frame 1, an installation bench arranged on both sides of the connecting rail 13 so that it can be raised and lowered, a joint rail 17 attached to the installation bench, a lever that is attached to the frame 1 so that it can rotate horizontally with one end connected to the installation bench, a helical tension spring that urges the lever so that one end of the lever moves circularly in the upward direction, and a cam follower 27 that is attached to the other end of a lever 19 and pushed by the bottom surface of a pit 100a with a sinking of the frame 1, thereby one end of the lever 19 is moved circularly in the downward direction. In this rail truck, end portions between these rails 13, 17 and 101 to 104 are formed diagonally such that they overlap and make contact horizontally.