To prevent leakage of blended gas or combustion gas from a side face or a mating part of a secondary rotary body by sealing a primary rotary body and arranging the secondary rotary body in the primary rotary body.

A chipped-circle-shape empty part is provided for each corner part of a rotor corner part, an intake rotary valve corner part and an exhaust gas rotary valve corner part. A circle-shape secondary rotary body (micro rotations 36, 37) sandwiching micro exits 30, 33 for entering and leaving which protrude toward respective corner parts are provided for the empty parts. The micro exits and the micro rotation are scraped out while slightly remaining areas near their outer circumferences so that a means for stopping gas is arranged in to a back side of the scraped-out portion and a pressing out means is also arranged in there. A wear-resistant sealing and the micro exits and the micro rotation can be slid from a front side and air-tightness of a sliding part is improved.