Scroll type fluid machinery, in which two stationary scrolls (2A, 2B) are fixed onto a housing (1), and form volume changing mechanisms (50A, 50B) with matching orbiting scrolls (3A, 3B). Three orbiting units (40) are located between the two volume changing mechanisms. Each orbiting unit comprises a rotating member (10) and a thrust-cancelling shaft (20). Assembly sets of the thrust-canceling shaft consist of turning elements and a connector, which in turn connects with orbiting scrolls through threads. There exists only circumferential constraint but no axial constraint between the connector and the turning element. Rotating turning element will rotate the connector, and thus move the two orbiting scrolls closer or farther through the threads on the connector. The rotating member of this invention further provides a larger space to the supporting bearings (14A, 14B) of the thrust-canceling shaft, and also eases component manufacturing, machinery's assembly and adjustment, and bearings' cooling.