A thermoelectric conversion element includes a magnetic body and an electromotive component. The magnetic body has a pipe shape. The electromotive component is arranged to at least one of an outer surface, an inner surface, and an inside of the magnetic body. The electromotive component contains a material having a spin orbit coupling. The magnetic body is magnetized in an axial direction and has a temperature gradient in a radial direction. The electromotive component is spirally arranged around the magnetic body along a circumferential direction.