A compressor comprising: a casing configured to store lubricant at a bottom of the casing; a compression mechanism provided in the casing to suck, and compress, a refrigerant; and an oil return member (100, 140) forming an oil return flow path that extends in a top-to-bottom direction to guide the lubricant discharged from the compression mechanism downward, characterised by the oil return flow path including: a uniform-cross-section flow path (133, 143a) having a uniform cross-sectional shape; and a varying-cross-section flow path (134, 144a) being continuous with a lower end of the uniform-cross-section flow path (133, 143a) and having a cross-sectional shape that varies, a lower end of the varying-cross-section flow path (134, 144a) forming an outlet of the oil return flow path and lying along an inner surface of the casing, in a case where a length of a cross section of the varying-cross-section flow path (134, 144a) along the inner surface of the casing is referred to as a width, and a length of the cross section of the varying-cross-section flow path (134, 144a) perpendicular to the inner surface of the casing is referred to as a thickness, the cross section of the lower end of the varying-cross-section flow path (134, 144a) having a greater width than a cross section of an upper end of the varying-cross-section flow path (134, 144a), the cross section of the lower end of the varying-cross-section flow path (134, 144a) having a smaller thickness than the cross section of the upper end of the varying-cross-section flow path (134, 144a). a casing configured to store lubricant at a bottom of the casing; a compression mechanism provided in the casing to suck, and compress, a refrigerant; and an oil return member (100, 140) forming an oil return flow path that extends in a top-to-bottom direction to guide the lubricant discharged from the compression mechanism downward, characterised by the oil return flow path including: a uniform-cross-section flow path (133, 143a) having a uniform cross-sectional shape; and a varying-cross-section flow path (134, 144a) being continuous with a lower end of the uniform-cross-section flow path (133, 143a) and having a cross-sectional shape that varies, a uniform-cross-section flow path (133, 143a) having a uniform cross-sectional shape; and a varying-cross-section flow path (134, 144a) being continuous with a lower end of the uniform-cross-section flow path (133, 143a) and having a cross-sectional shape that varies, a lower end of the varying-cross-section flow path (134, 144a) forming an outlet of the oil return flow path and lying along an inner surface of the casing, in a case where a length of a cross section of the varying-cross-section flow path (134, 144a) along the inner surface of the casing is referred to as a width, and a length of the cross section of the varying-cross-section flow path (134, 144a) perpendicular to the inner surface of the casing is referred to as a thickness, the cross section of the lower end of the varying-cross-section flow path (134, 144a) having a greater width than a cross section of an upper end of the varying-cross-section flow path (134, 144a), the cross section of the lower end of the varying-cross-section flow path (134, 144a) having a smaller thickness than the cross section of the upper end of the varying-cross-section flow path (134, 144a).