A load motor (1, 1a) for a chassis dynamometer apparatus which carries out a performance test of a vehicle, the load motor (1,1a) comprising: - a case having a peripheral wall portion, an end wall portion, and a hollow portion enclosed by the peripheral wall portion and the end wall portion; - a stator fixed to a radially inside surface of the peripheral wall portion; and - a rotor which is housed inside the hollow portion of the case, which is rotatably disposed radially inside the stator, and which can be coupled to a drive wheel coupling portion of the vehicle, - wherein, provided that a vehicle width direction is defined as an axial direction, that an outside of the vehicle width direction is defined as an axial outside, and that an inside of the vehicle width direction is defined as an axial inside, the peripheral wall portion of the case extends in the axial direction; the end wall portion of the case is disposed at an axial outside end of the peripheral wall portion; the case can be inserted from the axial outside into a tire house of the vehicle at the time of mounting in position the load motor (1, 1a) for the chassis dynamometer apparatus, characterized in that - the hollow portion of the case is configured to receive, by insertion thereinto, a brake disc and a brake caliper of the vehicle; - the stator has a coil that is wound therearound so that electric power supply is possible from the chassis dynamometer apparatus; and the rotor has: - a rotor frame (11, 111) extending radially outside at an axially outer position than the brake caliper in a state in which the rotor coupling portion (10, 101) is coupled to the drive wheel coupling portion; - a rotor circumferential wall portion which is connected to a radially outside end of the rotor frame (11, 111) and which extends axially inside from a connecting portion (11c, 111c) connected to the radially outside end of the rotor frame (11, 111); and magnets disposed in a plurality of pieces at a predetermined distance from one another along the circumferential wall portion, wherein the load motor (1, 1a) is so arranged that the brake caliper is inserted into a space radially inside the rotor circumferential wall portion in a state in which the rotor coupling portion (10, 101) is kept coupled to the drive wheel coupling portion. - a case having a peripheral wall portion, an end wall portion, and a hollow portion enclosed by the peripheral wall portion and the end wall portion; - a stator fixed to a radially inside surface of the peripheral wall portion; and - a rotor which is housed inside the hollow portion of the case, which is rotatably disposed radially inside the stator, and which can be coupled to a drive wheel coupling portion of the vehicle, - wherein, provided that a vehicle width direction is defined as an axial direction, that an outside of the vehicle width direction is defined as an axial outside, and that an inside of the vehicle width direction is defined as an axial inside, the peripheral wall portion of the case extends in the axial direction; the end wall portion of the case is disposed at an axial outside end of the peripheral wall portion; the case can be inserted from the axial outside into a tire house of the vehicle at the time of mounting in position the load motor (1, 1a) for the chassis dynamometer apparatus, characterized in that - the hollow portion of the case is configured to receive, by insertion thereinto, a brake disc and a brake caliper of the vehicle; - the stator has a coil that is wound therearound so that electric power supply is possible from the chassis dynamometer apparatus; and the rotor has: - a rotor frame (11, 111) extending radially outside at an axially outer position than the brake caliper in a state in which the rotor coupling portion (10, 101) is coupled to the drive wheel coupling portion; - a rotor circumferential wall portion which is connected to a radially outside end of the rotor frame (11, 111) and which extends axially inside from a connecting portion (11c, 111c) connected to the radially outside end of the rotor frame (11, 111); and