According to the embodiment, a storage device includes row lines arranged parallel to one another, column lines arranged parallel to one another to intersect with the row lines, and a memory cell disposed at each of intersections of the row lines and the column lines and including a resistance-change element and a diode connected in series to the resistance-change element. The diode includes a stack of a first semiconductor region containing an impurity of a first conductivity type, a second semiconductor region containing an impurity of the first conductivity type lower in concentration than in the first semiconductor region, and a third semiconductor region containing an impurity of a second conductivity type. An impurity concentration in the second semiconductor region of the diode in a first adjacent portion adjacent to the first semiconductor region is higher than that in a second adjacent portion adjacent to the third semiconductor region.