A scroll fluid machine comprising a first scroll rotated by a drive source, a second scroll eccentric from the central axis of the first scroll, the second scroll cooperating with the first scroll to compress fluid, a coupling which is provided on the outer end surface of one of said first and second scrolls and engaged with the one scroll at two positions in the periphery thereof so that the scrolls are movable in diametrical directions which are perpendicular to each other, respectively, and a pair of coupling arms which are provided on the other of the first and second scrolls and engaged with the coupling at two positions in the periphery thereof, in such a manner that the phantom line connecting the positions of engagement of said coupling arms is perpendicular to the phantom line connecting the positions of engagement of said coupling.