To assemble easily and highly precisely a drive scroll 5 having drive laps 4 and a drive scroll cap 6 provided at top end parts of the drive laps 4 coaxially in a scroll fluid machine 1.

A drive scroll 5 is provided with engaging parts 27 at elongated top end parts of its drive laps 4. Corresponding thereto, a drive scroll cap 6 is provided with engaged parts at a base end surface of its end plate 14. With the engaging parts 27 of the drive scroll 5 engaged with the engaged parts of the drive scroll cap 6, the elongated top end parts of the drive laps 4 are contacted with the base end surface of the end plate 14 of the drive scroll cap 6 without engagement in the part other than the engaged parts. Typically, the engaging parts 27 are projected parts formed in the inner end part and the outer end part of spirals of the drive laps 4, respectively, and the engaged parts are dented parts for receiving the projected parts.