Abstract: A spiral spring for reducing maximum stress value and variations in stress distribution. The spiral spring is elastically deformable from a minimally to maximally deformed state. In maximally deformed state, the spiral spring includes a non-contact section, wherein at least some spring material portions are adjacent in radial direction not contacting each other, and a contact section, wherein all spring material portions are adjacent in radial direction contacting each other. An inner reference portion is corresponding to a central angle of 80° or more and 160° or less about a spiral center along a direction of spiral portion extension with a reference line connecting the spiral center and outer contact portion, wherein the outer end portion and outer fixing member contact in maximally deformed state, the inner reference portion being on a radially spiral portion inner side. The contact section is on a radially inner reference portion outer side.