To obtain a rotary compressor in which compressor efficiency is improved by suppressing heat expansion of a low temperature coolant gas in a first half of compression process.

A rotary compressor includes: annular cylinders 121S, 121T in which intake holes 135S, 135T and vane grooves 128S, 128T are provided radially in side expansion parts 122S, 122T; and a compression section which includes annular pistons fitted to an eccentric part of a rotary shaft and revolving inside of the cylinders along inner walls of the annular cylinders, and vanes protruding from the inside of the vane grooves into the cylinders and abutted to the annular pistons, and discharges a compression coolant gas into a compressor casing 10. Low pressure side cylinder parts 121Sa, 121Ta at a side of the intake holes of a centerline P passing through the vane grooves of the annular cylinders and high pressure side cylinder parts 121Sb, 121Tb at an opposite side of the centerline P are formed from different materials and joined to each other, and the low pressure side cylinder parts are formed from a material of which heat conductivity is lower than that of a material for the high pressure side cylinder parts.