Scroll Fluid Machine

A scroll fluid machine comprising two scroll members each of which has a spiral body formed on a base plate, the scroll members being engaged to relatively gyrate such that a hermetic space formed by both scroll members is increased or reduced to make fluid expand or compress the fluid, wherein:

• the scroll fluid machine is configured such that a seal member is provided between a rear surface of one of the scroll members and a stationary member to divide a space formed between the rear surface and the stationary member into an inner side space and an outer side space, the inner side space inside the seal member being subjected to a pressure substantially corresponding to a discharge pressure, the outer side space outside the seal member being subjected to a pressure lower than that in the inner side space to press the one scroll member against the other scroll member;
• and
• the shape of the spiral body of each scroll member is configured such that the width of a groove of the spiral body of the scroll member and the thickness of a tooth of the spiral body decrease from a central portion toward an outer side of the spiral body over a part of or the whole of the spiral body.