According to one embodiment, a magnetoresistive element manufacturing method is provided. In this magnetoresistive element manufacturing method, a first ferromagnetic layer, tunnel barrier layer, and second ferromagnetic layer are sequentially formed on a substrate. A conductive hard mask is formed on the second ferromagnetic layer. The hard mask is patterned. A hard layer is formed on the side surface of the hard mask. The second ferromagnetic layer, tunnel barrier layer, and first ferromagnetic layer are processed by IBE in an oblique direction by using the hard mask and hard layer as masks. The IBE etching rate of the hard layer is lower than that of the hard mask.