To provide a light lifting device used even for the narrow stairs of a vessel or the like.

Since both frames 1A and 1B are placed oppositely to each other keeping an interval and respectively disposed in both sides of stairs A, the user of the stairs A is allowed to ascend/descend between the frames 1A and 1B, and in this case each of the widths of the frames 1A and 1B is about 50mm and the dimension of 300 to 550mm is a width for passing when the width of the stairs is 400 to 650mm, and thus the user easily ascends/descends even while a hoist gear is installed in the stairs A. Further, since the frames are disposed in both sides of the stairs A and a load base 5 is supported between both frames, each of the widths of the frames is formed to be narrow in dimension and the entire device is reduced in weight.