An outboard motor lifting device includes a hydraulic source, a first oil channel connecting the hydraulic source with a second chamber of a tilt cylinder, a second oil channel connecting the first oil channel with a second chamber of a trim cylinder, a third oil channel connecting the hydraulic source with a first chamber of the tilt cylinder, a check valve provided between the second chamber of the tilt cylinder and a connection position between the first and second oil channels, a fourth oil channel connected to the third oil channel, and a switch valve provided on the second oil channel and connected with the fourth oil channel. The switch valve has a connection state where communication between the first oil channel and the second chamber of the trim cylinder is closed, and communication between the fourth oil channel and the second chamber of the trim cylinder is open.