PURPOSE: To form an engine main body compactly by turning a disc plate valve which is installed in a cylinder head and in which double laminated upper and lower parts are rotated in opposite directions each other, by means of rotation of a crank shaft.

CONSTITUTION: A shaft 1 is rotated by rotation of a crank shaft to transfer the rotation to the ring gear of a disc plate valve 3. A shaft 2 is rotated in opposite direction to transfer rotation to the ring gear of a disc plate valve 4. Since the disc plate valve 3 is connected to a disc valve 5 through respective ring gears, the disc plate valve 5 is moved. A disc plate valve 6 is also moved by the disc plate valve 4 in the same way. Therefore, each disc plate valve of a piston is moved. It is, thus possible to form an engine main body compactly so as to stand high rotation of a valve mechanism.