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 , <EOS>