A compressor includes: a compression space with an annular shape comprising an inner circumferential surface and an outer circumferential surface; and a discharge opening formed in a direction parallel to a shaft direction of the compressor, to discharge a refrigerant compressed in the compression space, wherein a first portion of a cross-sectional area of the discharge opening overlaps a portion of a cross-sectional area of the compression space, a second portion of the cross-sectional area of the discharge opening does not overlap the cross-sectional area of the discharge opening, and the ratio of the non-overlapping second portion of the cross-sectional area of the discharge opening to the entire cross-sectional area of the discharge opening is 0.1 or less. With such a configuration, a dead volume generated in the compression space can be reduced, and thus compressor efficiency can be enhanced.