A rotary compressor comprising: a drive shaft comprising an eccentric shaft portion (15, 16) at a predetermined axial location; a cylinder body (19, 20) forming a cylinder chamber (17, 18) corresponding to the eccentric shaft portion (15, 16); an upper bearing mounted on an upper surface of the cylinder body (19, 20) and a lower bearing mounted on a lower surface of the cylinder body (19, 20), the upper and lower bearings (23, 24) defining the cylinder chamber (17, 18) and rotatably supporting the drive shaft; a rotor (25, 26) fitted to the eccentric shaft portion (15, 16) to rotationally move within the cylinder chamber (17, 18); and a bearing ring (33, 34) being a sliding bearing provided between the eccentric shaft portion (15, 16) and the rotor (25, 26), wherein axial widths of the eccentric shaft portion (15, 16) and the bearing ring (33, 34) are the same and are smaller than an axial width of the rotor (25, 26), wherein the drive shaft comprises two eccentric shaft portions at upper and lower locations with a predetermined spacing therebetween, characterised in that two upper and lower compression mechanisms (6A, 6B) are provided with a separator plate therebetween, each of the compression mechanisms (6A, 6B) comprising a cylinder body (19, 20) forming a cylinder chamber (17, 18) corresponding to one of the eccentric shaft portions (15, 16) and a rotor (25, 26) fitted to the corresponding eccentric shaft portion (15, 16) to rotationally move within the corresponding cylinder chamber (17, 18), and wherein a bearing ring (33, 34) being a sliding bearing provided is provided between each eccentric shaft portion (15, 16) and each rotor (25, 26), and wherein the eccentric shaft portion at the lower location has a diameter smaller than a diameter of the eccentric shaft portion at the upper location, the eccentric shaft portion at the lower location being positioned farther from an electric motor coupled to one end of the drive shaft, the eccentric shaft portion at the upper location being positioned closer to the electric motor. a drive shaft comprising an eccentric shaft portion (15, 16) at a predetermined axial location; a cylinder body (19, 20) forming a cylinder chamber (17, 18) corresponding to the eccentric shaft portion (15, 16); an upper bearing mounted on an upper surface of the cylinder body (19, 20) and a lower bearing mounted on a lower surface of the cylinder body (19, 20), the upper and lower bearings (23, 24) defining the cylinder chamber (17, 18) and rotatably supporting the drive shaft; a rotor (25, 26) fitted to the eccentric shaft portion (15, 16) to rotationally move within the cylinder chamber (17, 18); and a bearing ring (33, 34) being a sliding bearing provided between the eccentric shaft portion (15, 16) and the rotor (25, 26), wherein axial widths of the eccentric shaft portion (15, 16) and the bearing ring (33, 34) are the same and are smaller than an axial width of the rotor (25, 26), wherein the drive shaft comprises two eccentric shaft portions at upper and lower locations with a predetermined spacing therebetween, characterised in that two upper and lower compression mechanisms (6A, 6B) are provided with a separator plate therebetween, each of the compression mechanisms (6A, 6B) comprising a cylinder body (19, 20) forming a cylinder chamber (17, 18) corresponding to one of the eccentric shaft portions (15, 16) and a rotor (25, 26) fitted to the corresponding eccentric shaft portion (15, 16) to rotationally move within the corresponding cylinder chamber (17, 18), and wherein a bearing ring (33, 34) being a sliding bearing provided is provided between each eccentric shaft portion (15, 16) and each rotor (25, 26), and wherein the eccentric shaft portion at the lower location has a diameter smaller than a diameter of the eccentric shaft portion at the upper location, the eccentric shaft portion at the lower location being positioned farther from an electric motor coupled to one end of the drive shaft, the eccentric shaft portion at the upper location being positioned closer to the electric motor.