PURPOSE: To reduce the flow loss and pressure loss and generate highly efficient pulse waves by arranging valve element sections interrupting or communicating a passage between a pressurizing port and a respiratory port and a passage between a negative- pressure port and the respiratory port when a rotary valve is rotated to the preset position on the rotary valve.

CONSTITUTION: A rotary valve 51 is constituted of a pair of valve element sections 53, 54 extended from the center section of the axial direction of a rotary shaft 44 to one side of the axial direction and a pair of valve element sections extended in the other side of the axial direction, and the valve element sections 53, 54 are formed into a circular arc-shaped cross section notched with the upper and lower portions of a cylinder coaxial with the rotary shaft 44 into a rectangular shape. The valve element sections 55, 56 are formed into a circular arc-shaped cross section notched with the right side and left side portions of a cylinder coaxial with the rotary shaft 44, and the valve element sections 53, 54 and the valve element sections 55, 56 are set to positions staggered with the phase relation by 90°. The output direction and input direction of the rotary valve 51 can be arranged in the same direction, the passage can be formed into nearly a straight shape, and the passage loss can be reduced.