An object of the present invention is to provide nonvolatile, rewritable, easily-manufactured, and inexpensive storage element, storage device, and semiconductor device, which are superior in switching characteristics and which has low operation voltage. In an element including a first conductive layer, a second conductive layer facing the first conductive layer, and a layer containing at least one kind of an organic compound provided between the first conductive layer and the second conductive layer, the organic compound can be electrochemically doped or dedoped. By feeding current in this element, the organic compound provided between the conductive layers is electrochemically doped, i.e., electrons are transported, whereby the conductivity can be increased by about three to ten digits.