To provide a rotary power machine for obtaining rotational power and generating electric energy with use of terrestrial gravity.

A plurality of support plates 2 are radially disposed at equal intervals on a base 1. Root bases of the support plates are embedded in the base, springs are put on intermediate portions and weight bodies are fitted on tips. These are connected to the base through the springs. With initial rotation by manual start, on the right side, the weight bodies are extended right and weight by terrestrial gravity, and on the left side, the springs are compressed with the weight bodies pulled back inwards and gravity balance between the left and right weight bodies is lost so that the base is rotated clockwise continuously.