According to one embodiment, a manufacturing method of a magnetoresistive memory device includes forming a first magnetic layer on a substrate, forming a magnetoresistive effect element on the first magnetic layer, forming a mask on a part of the magnetoresistive effect element, selectively etching the magnetoresistive effect element using the mask, forming a sidewall insulating film on a sidewall of the magnetoresistive effect element exposed by the etching, selectively etching the first magnetic layer using the mask and the sidewall insulating film and forming a deposition layer containing a magnetic material on a sidewall of the first magnetic layer and the sidewall insulating film, and introducing ions into the deposition layer.