PURPOSE: To improve performance by means of a simple, small-sized and inexpensive constitution, without entailing any system complication and enlargement in size in addition to a rise in manufacturing cost even in the case where it is used as an air dilatational refrigerator.

CONSTITUTION: A motor-operated element 2 and a scroll compressive element 3 are stored in a hermetically sealed vessel 1, and this scroll compressive element 3 is composed of a driving scroll 22 connected to the motor-operated element 2, a driven scroll 24 concentrically set up with this driving scroll 22, and an intermediate scroll 25 being set up in an interval between this driven scroll 24 and the driving scroll 22, and eccentrically set up in both these scrolls 22 and 24. In this constitution, those of driving, driven and intermediate scrolls 22, 24 and 25 are rotated in the same direction.