Provided is a thermoelectric conversion element having a greater Seebeck coefficient (S) than the conventional ones. In a thermoelectric conversion element: a nonmagnetic Heusler alloy film (10), a ferromagnetic Heusler alloy film (11) and a nonmagnetic layer (12) are stacked in the named order; a pair of electrodes (23, 24) are disposed for deriving, in accordance with a temperature gradient occurring in parallel to the direction of magnetization (41) of the ferromagnetic Heusler alloy film, an electromotive force occurring perpendicularly to the direction of magnetization of the ferromagnetic Heusler alloy film; a pair of electrodes (21, 22) are disposed for deriving an electromotive force occurring in parallel to the direction of magnetization of the ferromagnetic Heusler alloy film; and the electromotive forces occurring due to an ordinary Seebeck effect and a spin Seebeck effect are simultaneously derived.