A nonvolatile storage device includes a first conductive layer disposed on a substrate, a contact plug including a conductive material and disposed on the first conductive layer, a variable resistance element covering the upper surface of the contact plug, resistance of the variable resistance element changing in accordance with an voltage applied to the variable resistance element, one single insulating layer that is directly or indirectly in contact with a sidewall of the contact plug and that is directly or indirectly in contact with a sidewall of the variable resistance element, and a second conductive layer disposed on the variable resistance element.