A horizontal type rotary compressor including a compression element having a cylinder, a shaft having a crank thereon, a pair of side plates concurrently serving both as bearings of the shaft and as side walls of the cylinder, a roller fitted onto the crank, and a vane so arranged as to slide in a groove of the cylinder and have a tip end thereof contacted with the roller rotating in accordance with the rotation of the crank and an appropriate end thereof urged by a spring to make a reciprocating movement along the groove are provided within a case. A pumping chamber is defined by a rear face of the vane, the groove of the cylinder and the side plates. One of the side plates is formed with a suction port capable of sucking thereinto the oil within the case while the other of the side plate is formed with a discharge port for transmitting the oil in the pumping chamber to an oil feeding passage. An oil feeder means for use in the horizontal type rotary compressor is a space provided at the exit of the suction port of the side plate having the suction port and the suction port opens downwardly so that the feeding of a sufficient or stable amount of oil is ensured even when the surface level of the oil is lowered.