To provide a hook device and a boat lifting device capable of releasing a connection tool even under a loaded condition.

The hook device 10 comprises a hook 12 to be turnably supported via a pin 11, a hook urging spring 13 for urging the hook 12 in the opening direction, a cam 14 for turning the hook 12 in the closing direction against the hook urging spring 13, a lever 15 for turning the cam 14, and a lever urging spring 16 for urging the lever 15 in the closing direction. The hook 12 is turned in the closing direction following the cam, and engaged with a shackle 8. On the other hand, when the hook 12 is turned in the opening direction following the cam 14, the shackle 8 is released from the hook 12.