Reduced-pressure device

A reduced-pressure device for wound treatment comprising:

• a housing having recesses on sidewalls thereof;
• an air pressure storage unit installed in the housing, comprising:
• a pressure storage container;
• a piston assembly slidably installed in the pressure storage container;
• and
• a piston spring installed between the base of the pressure storage container and the piston assembly;
• and
• a compression unit mounted on the piston assembly of the air pressure storage unit, including a pressing element and a turntable, wherein for generating a negative pressure, the pressing element is pulled out of the recesses and rotated to a predetermined position, the pressing element is pressed down into an opening formed in a piston cover to compress the piston assembly down to generate the negative pressure in the pressure storage container and the pressing element is pulled up again and rotated back to an original position for being accommodated into the recesses.