A reservoir element includes a plurality of magnetoresistive effect elements each having a first ferromagnetic layer, a non-magnetic layer and a second ferromagnetic layer laminated in a first direction, and separated from each other, a spin orbit torque wiring that faces a part of at least one of the plurality of magnetoresistive effect elements, and a spin-conductive layer that connects at least the magnetoresistive effect elements closest to each other of the plurality of magnetoresistive effect elements, and conducts spins, wherein, the magnetoresistive effect elements are seen from the first direction, the second ferromagnetic layer overlaps part of the first ferromagnetic layer, the spin orbit torque wiring faces a first portion that does not overlap the second ferromagnetic layer in the first ferromagnetic layer when seen from the first direction, and the spin-conductive layer faces at least the first ferromagnetic layer each of the closest magnetoresistive effect elements.