Scroll type fluid machine

A scroll type fluid machine comprising a fixed scroll, a movable scroll which engages said fixed scroll to form a fluid pocket being moved in a scroll radial direction, a crankshaft which engages said movable scroll to drive said movable scroll, and a housing which is provided with a bearing supporting said crankshaft, said movable scroll being orbited relative to said fixed scroll by a drive torque transmitted to through said crankshaft, characterized in that said fixed scroll and said housing form a non-orbiting part, and provided is a rotation-preventing member which extends between at least one of said fixed scroll and said housing forming said non-orbiting part and said movable scroll and which prevents said movable scroll from rotating, and also provided to said rotation-preventing member is a mechanism for making said rotation-preventing member movable, said mechanism permitting said rotation-preventing member's own movement required for permission of an orbital movement of said movable scroll by said rotation-preventing member.