Provided is a magnetoresistance effect device comprising a magnetoresistance effect element including a first ferromagnetic layer, a second ferromagnetic layer and a spacer layer, and a high-frequency signal line. The high-frequency signal line includes an overlapping part disposed at a position overlapping the magnetoresistance effect element and a non-overlapping part disposed at a position not overlapping the magnetoresistance effect element in a plan view from a stacking direction. At least a part of the non-overlapping part is disposed below the overlapping part in the stacking direction, assuming that the overlapping part is above the magnetoresistance effect element in the stacking direction.