A scroll fluid machine comprises a fixed scroll (20) and an orbiting scroll that engages with the fixed scroll (20) to form a compression chamber between the fixed and orbiting scrolls. Near the outer circumference of the fixed and/or orbiting scroll, an annular dust-seal groove (27) is provided. In the groove, a dust seal fits to prevent a gas from coming into the compression chamber or from leaking out of the compression chamber. In the dust-seal groove (27), an annular holder (5) or piece is provided to prevent heat from transferring to the dust seal.