The invention discloses and provides a tidal current power generation device which comprises a horizontal impeller, a vertical impeller, a first magnetic coupling coupler, a second magnetic coupling coupler, a first gear speed increasing box, a second gear speed increasing box, a first generator, a second generator, a gear tumbler, a sealed cabin, a speed-limit control mechanism and an energy storage device. The tidal current power generation device has the advantages of combining horizontal shaft tidal current power generation with vertical shaft tidal current power generation, being good in self-starting performance, adapting to directional changes of incoming flow, being high in power generation efficiency, beneficial to the design, debugging and maintenance of an electrical control system due to an integral suspension structure, capable of connecting with a fixing anchor chain of a sea surface wave power generation device through a supporting truss structure and hierarchically arranged below the sea surface in a suspension mode to form into an ocean current wave power generation system, achieving good utilization of the ocean energy and the like.