Vehicular rotational apparatus

A compressor (C) includes a housing, a rotary shaft (16), a pulley (17), an electric motor (77), a pulley one-way clutch (66), and a motor one-way clutch (83). The shaft (16) is rotatably supported by the housing. The pulley (17) is operably connected to the shaft (16) and includes a power transmission portion. When power is transmitted from a vehicular engine to the power transmission portion, the pulley (16) is rotated. The electric motor (77) rotates the shaft (16) and includes a rotor, which is operably connected to the shaft. At least part of the electric motor (77) overlaps the power transmission portion in the axial direction of the shaft (16). The pulley one-way clutch (66) is located between the pulley (17) and the shaft (16) and selectively permits and prevents power transmission between the pulley (17) and the shaft (16). The motor one-way clutch (83) is located between the rotor and the shaft (16) and selectively permits and prevents power transmission between the rotor and the shaft (16).