A scroll type fluid machine (1) has a rotation prevention mechanism (36) consisting of a circular hole (40) that is formed in a base portion (20a) and of a pin (38) that is press fitted in a press fit hole (42) in a rear face (32b) and is loosely fitted in the circular hole (40). The rotation prevention mechanism (36) prevents rotation of a movable scroll (32) without obstructing revolving motion of the movable scroll (32). A space (56) is formed between the pin (38) and the press fit hole (42) by press fitting and fixing the pin (38) to the press fit hole (42). The rotation prevention mechanism (36) has a communication path (58) for connecting the space (56) to the housing (2).
