An optical component mounting structure includes an elastic member and a mounting portion. The elastic member applies pressure to an optical component toward a flat surface portion of a base. The mounting portion is provided at the base and mounts the elastic member. The elastic member has a pressing portion, a holding portion, and a positioning hole. The pressing portion has a tongue piece shape and elastically comes in contact with a light guide member. The holding portion supports one end of the pressing portion and holds elastically the mounting portion of the base. The positioning hole is formed through the holding portion and is to be engaged with each of a pair of positioning convex portions provided at the mounting portion of the base.