According to the present invention, a reciprocating compressor with a rotary valve comprises a cylinder block with plural cylinder bore, a drive shaft which is supported and permitted to rotate in relation to the cylinder block, a piston which is housed in the cylinder bore and allowed to reciprocate therein, a power transmitting unit which connects the piston and drive shaft, a rear housing wherein an intake chamber and exhaust chamber are formed, and a rotary valve which rotates with the drive shaft and is installed in the inner surface of a coupling hole formed in the cylinder block and permitted to slide and rotate therein. In the inner circumference of the cylinder block, connection holes are respectively connected to the cylinder bore. A bypass unit is included between the coupling hole and rotary valve and bypasses the refrigerant remaining in the connection hole of one cylinder bore during the compressive stroke of the piston, then discharges it through the connection hole of another cylinder bore.