To provide a small capacity rotary compressor allowing its top plate and bottom plate to be co-used with a model having a large cylinder capacity and assuring a high productivity by reducing sliding loss of a rotary shaft, which leads to prevention of COP from worsening.

A small capacity rotary compressor 2 having a small cylinder capacity uses a compressor casing having the same size as that of a large capacity rotary compressor 1 with a large cylinder capacity, wherein diameters of a main shaft portion and a sub-shaft portion 151a of the compressor 2 are made the same as those of a main shaft portion and a sub-shaft portion of the rotary shaft of the large capacity rotary compressor 1, and a top plate and a bottom plate 160S are made the same as a top plate and a bottom plate of the large capacity rotary compressor 1, and a sliding length H₂ of the sub-shaft portion 151a is made smaller than a sliding length of the sub-shaft portion of the large capacity rotary compressor 1.