PURPOSE: To guarantee silent and balanced rotation of a main shaft and reduce magnetic attraction, gap higher harmonies and vibrational noise in a motor.

CONSTITUTION: A rotary compressor comprises a motor, a main shaft 5 connected rotatably by the motor, and four cylinders 30 arranged in the same plane. Each of the cylinders comprises a roller 6 eccentrically mounted to a roller shaft, and a vane 32 slidably disposed in a body of the cylinder and always being in contact with the roller. The roller shaft is connected to the main shaft via a gear, and the roller shaft rotates simultaneously when the main shaft is rotated. A compression chamber 31 of the cylinder is divided by the vane into a suction area 31A of the compression chamber and a discharge area 31B of the compression chamber. The compression chamber is arranged symmetrically about the main shaft so as to compensate for a vibration force generated by other cylinders, thus permitting silent and balanced rotation of the rotary compressor.