A pin insertion hole is formed in an outer member, and a pin groove is formed in an inner member. A positioning device includes a pin entering the pin insertion hole and the pin groove, and a groove contact member coming in contact with a groove side surface of the pin groove. In one member of the pin and the groove contact member, a position restriction concave portion recessed in a direction away from the other member is formed in a portion facing the other member. In the other member, a claw portion entering the position restriction concave portion and coming into contact with the position restriction concave portion is formed as a portion of the other member is plastically deformed.