To provide a hook device capable of releasing a connector even in a loaded state, and a boat lifting device.

The hook device 9 for attachably/detachably connecting a connector 61 to a connection base 10 comprises hook return springs 47, 48 which couple a ball 70 with the connector 61, couple a pair of first and second hooks 41, 42 for holding the ball 70 with the connection base 10 in an opening/closing manner, and urge the first and second hooks 41, 42 in a closing direction, a retainer 75 for restricting the first and second hooks 41, 42 at the closing position, a retainer return spring 80 for urging the retainer 75 in the restricting direction, and a lever 50 for driving the retainer 75 in the unrestricting direction against the retainer return spring 80.