To surely seal the top portion of a scroll lap in an oil free scroll fluid machine.

In an oil free scroll fluid machine having a fixed scroll 2 fixed to a casing 5 and a swing scroll 4 having a scroll lap 23 engaged with the scroll lap 21 of the fixed scroll 2, the swing scroll 4 being designed to be freely swingable without rotating around the shaft core 60 of a driving shaft 13 by itself, a seal groove 28 is formed in the top portion of each of the scroll laps 21, 23 of the fixed scroll 2 and the swing scroll 4, a chip seal 29 is fitted in the seal groove so as to be freely detachable therefrom, and voids are formed in the side surface 64 and lower surface 61 of the chip seal confronting the seal groove so as to be insulated from one another and disposed at proper intervals over the entire length in the scroll direction of the scroll lap.