To adjust chip clearance in response to a variation in an operation state of a compressor.

A contraction liner 16 is formed in a cylindrical shape in a position corresponding to a moving blade cascade of an inner peripheral surface of a casing 12, and is moved in the radial direction by a variable mechanism 18. The variable mechanism has a pump 26 and a pump controller 28. The casing has a recessed part 32 formed in a circumferential belt shape on an inside surface. The contraction liner changes its inner diameter by sliding between the inside surface and a recessed part side surface by pump pressure in a state of being fitted in this recessed part.