PURPOSE: To stimulate effective pressure points over a wide range from the back to the buttocks by continuously switching the jetting-out port of jet streams.

CONSTITUTION: This unit is equipped with a bathtub 1, sucking port 23 provided at the bathtub 1 for sucking cold water or hot water, and plural jetting-out ports 2 vertically arranged for jetting-out jet streams while mixing air led from air flow-in ports 4. A pump 22 is provided to suck cold water or hot water from the sucking port 23 and to jet it out of the jetting-out ports 2, and switching ports 5 are provided to selectively switch the flow of cold water or hot water to the plural jetting-out ports 2. Further, a motor 12 is provided to continuously switch the switching ports 5. Therefore, since the switching ports are continuously operated by a driving source such as the motor, etc., the jet streams are continuously switched from the back to the buttocks, and effects as an automatic massage machine can be obtained.