A rotary compressor comprising: a first cylinder; a first piston that has a cylindrical shape and revolves along an inner wall surface of the first cylinder and forms a first compression chamber for compressing a fluid between the first piston and the inner wall surface of the first cylinder; and a drive shaft that is rotatable and comprises a first eccentric portion that is eccentric in a first direction with respect to a rotational center axis and to which the first piston is fitted, wherein the drive shaft comprises: a first shaft portion that is rotatably supported by a first bearing formed on an end plate for closing one end face of the first cylinder and has a cylindrical shape coaxial with the rotational center axis of the drive shaft; and a first coupling portion that couples the first shaft portion with the first eccentric portion and is configured to satisfy R e1 - e 1 < R 1, wherein R e1 is a radius of the first eccentric portion, R 1 is a radius of the first shaft portion, and e 1 is eccentricity of the first eccentric portion, and the first coupling portion is formed such that its outer surface does not extend out of an outer surface of the first eccentric portion in a radial direction of the drive shaft, and includes a reinforcement portion with its outer surface positioned outside an outer surface of the first shaft portion in a radial direction of the drive shaft, characterized in that the first coupling portion is formed inside the end plate. a first cylinder; a first piston that has a cylindrical shape and revolves along an inner wall surface of the first cylinder and forms a first compression chamber for compressing a fluid between the first piston and the inner wall surface of the first cylinder; and a drive shaft that is rotatable and comprises a first eccentric portion that is eccentric in a first direction with respect to a rotational center axis and to which the first piston is fitted, wherein the drive shaft comprises: a first shaft portion that is rotatably supported by a first bearing formed on an end plate for closing one end face of the first cylinder and has a cylindrical shape coaxial with the rotational center axis of the drive shaft; and a first coupling portion that couples the first shaft portion with the first eccentric portion and a first shaft portion that is rotatably supported by a first bearing formed on an end plate for closing one end face of the first cylinder and has a cylindrical shape coaxial with the rotational center axis of the drive shaft; and a first coupling portion that couples the first shaft portion with the first eccentric portion and is configured to satisfy R e1 - e 1 < R 1, wherein R e1 is a radius of the first eccentric portion, R 1 is a radius of the first shaft portion, and e 1 is eccentricity of the first eccentric portion, and the first coupling portion is formed such that its outer surface does not extend out of an outer surface of the first eccentric portion in a radial direction of the drive shaft, and includes a reinforcement portion with its outer surface positioned outside an outer surface of the first shaft portion in a radial direction of the drive shaft, characterized in that the first coupling portion is formed inside the end plate. is formed such that its outer surface does not extend out of an outer surface of the first eccentric portion in a radial direction of the drive shaft, and includes a reinforcement portion with its outer surface positioned outside an outer surface of the first shaft portion in a radial direction of the drive shaft,