A rotary compressor comprising: a cylinder having a cylinder chamber in an inner portion thereof and provided with an approximately circular bush groove at a position adjacent to the cylinder chamber; a piston housed in the cylinder chamber and configured to rotate eccentrically; a blade integrally formed with the piston and separating the cylinder chamber into a low-pressure chamber and a high-pressure chamber; and a pair of bushes (61, 71) each having a substantially semicircular shape and including a curved surface facing away from the blade and a surface facing the blade, said surface facing the blade including a flat surface, the pair of bushes (61, 71) being fitted in the bush groove such that the flat surfaces (61a, 71a) face each other, and the pair of bushes holding the blade placed between the flat surfaces in such a manner that allows the blade to swing, wherein a curved surface of at least the bush on a low-pressure side slides with an inner surface of the bush groove, while being pushed toward the cylinder chamber, due to a pressure difference between a low pressure in the cylinder chamber and a high pressure in a back pressure space opposed to the cylinder chamber with respect to the bush, the rotary compressor being characterised in that the surface of at least the bush on the low-pressure side is provided with a crowned portion at an edge of the bush closer to the cylinder chamber, the crowned portion extending from a crowning start position toward an edge of the at least one bush closer to the cylinder chamber, wherein the flat surface is orthogonal to a center line of the bush, which is a straight line passing through a center of curvature of the curved surface of the bush and a mid-point of a length L of an imaginary plane extending along the flat surface of the bush, the length L of the imaginary plane representing the length of the surface facing the blade before being subjected to the crowning, and wherein L'[mm] represents a length between the edge of the at least one bush closer to the cylinder chamber and the crowning start position, wherein a parameter α, which is a ratio of L' to L (L'/L), is determined to satisfy 0.2 ≤ α < 0.5, with L in mm. a cylinder having a cylinder chamber in an inner portion thereof and provided with an approximately circular bush groove at a position adjacent to the cylinder chamber; a piston housed in the cylinder chamber and configured to rotate eccentrically; a blade integrally formed with the piston and separating the cylinder chamber into a low-pressure chamber and a high-pressure chamber; and a pair of bushes (61, 71) each having a substantially semicircular shape and including a curved surface facing away from the blade and a surface facing the blade, said surface facing the blade including a flat surface, the pair of bushes (61, 71) being fitted in the bush groove such that the flat surfaces (61a, 71a) face each other, and the pair of bushes holding the blade placed between the flat surfaces in such a manner that allows the blade to swing, wherein a curved surface of at least the bush on a low-pressure side slides with an inner surface of the bush groove, while being pushed toward the cylinder chamber, due to a pressure difference between a low pressure in the cylinder chamber and a high pressure in a back pressure space opposed to the cylinder chamber with respect to the bush, the rotary compressor being characterised in that the surface of at least the bush on the low-pressure side is provided with a crowned portion at an edge of the bush closer to the cylinder chamber, the crowned portion extending from a crowning start position toward an edge of the at least one bush closer to the cylinder chamber, wherein the flat surface is orthogonal to a center line of the bush, which is a straight line passing through a center of curvature of the curved surface of the bush and a mid-point of a length L of an imaginary plane extending along the flat surface of the bush, the length L of the imaginary plane representing the length of the surface facing the blade before being subjected to the crowning, and wherein L'[mm] represents a length between the edge of the at least one bush closer to the cylinder chamber and the crowning start position, wherein a parameter α, which is a ratio of L' to L (L'/L), is determined to satisfy 0.2 ≤ α < 0.5, with L in mm.