The invention relates to a supercharger, and provides an active deep sea water supercharger. The supercharger comprises an oil filling cavity, a crankshaft connecting rod component, a plunger, a high pressure cavity, a distribution valve, an overflow valve and a pressure compensator communicated with the oil filling cavity through a capillary oil pipe joint, wherein lubricating oil is fully filled in the pressure compensator and the oil filling cavity which are mutually communicated. The supercharger can be directly applied in a deep sea environment; the integral designed structure of a connecting rod can lighten the abrasion of the connecting rod and a crankshaft; cone valve distribution can greatly improve the response frequency; the oil filling cavity, the high pressure cavity, the connecting rod and the plunger are matched by adopting proper materials, therefore, the mass of the whole supercharger is lightened and the corrosion resistance and the abrasion resistance of the supercharger are enhanced.