A scroll compressor includes a pressing mechanism and a back-flow prevention mechanism. The pressing mechanism includes a back-pressure chamber facing a back surface of a movable-scroll end plate, and a back-pressure supply path arranged to allow the back-pressure chamber to communicate with a compression chamber which is in a state right before the compression chamber communicates with an outlet port or a state in which the compression chamber communicates with the outlet port. The back-flow prevention mechanism allows refrigerant of the back-pressure supply path to flow from the compression chamber to the back-pressure chamber, and prevents fluid of the back-pressure supply path from returning from the back-pressure chamber to the compression chamber.