A fixing apparatus that fixes a robot having a robot main body mounted on a truck to an external structure in a positioning state, the truck being capable of traveling on a floor surface, the apparatus including: a first unit provided in one of the robot and the external structure; a second unit provided in the other of the robot and the external structure; a positioning mechanism that determines relative relation between the truck and the robot, and the external structure by use of the first unit and the second unit; and a lock mechanism that locks the truck and the robot, and the external structure.