To provide an optical scanner capable of preventing rattling of a swing shaft portion without enlargement and an image projection device using the optical scanner.

An optical scanner includes a swing shaft portion, a swing body that is provided to the swing shaft portion and has a reflection surface, a base table that supports the swing shaft portion, and a driving unit that swings the swing shaft portion. To the base table, a first bearing that supports one end of the swing shaft portion and a second bearing that supports the other end of the swing shaft portion are provided. The swing shaft portion has a tapered portion formed into a taper shape at one end. The first bearing is a thrust bearing that engages with the tapered portion, and the second bearing is a radial bearing that comes into contact with an outer peripheral surface of the swing shaft portion.