A primary groove, into which a primary vane is slidably fitted, and a primary rotor-side suction passage, which conducts refrigerant of a shaft-side suction passage of a shaft to a primary compression chamber, are formed at a primary rotor. The primary groove is shaped into a form that extends from an inner peripheral side toward an outer peripheral side and extends toward a rear side with respect to a rotational direction, and the primary rotor-side suction passage is shaped into a form that extends from the inner peripheral side toward the outer peripheral side and extends and tilts toward a front side with respect to the rotational direction. A fluid outlet of the primary rotor-side suction passage opens at a location that is immediately after the primary groove on the rear side of the primary groove with respect to the rotational direction.