The present invention realizes a smaller and light reciprocating compressor with higher efficiency and longer life time, producing lower noise and less vibration. A reciprocating compressor 1 includes: a motor having a motor shaft 2s four cylinders provided in a direction perpendicular to an axial direction of the motor shaft 2s and four pistons 5 each having a piston head part 5h and a rod part 5R formed integrally, the piston head part 5h fitting into a corresponding one of the four cylinders 4 in a reciprocable fashion, and the rod part 5R being rotatably installed to an eccentric shaft 17 fixed to the motor shaft 2s.
