To provide an insulated electric wire which has high heat resistance, and in which peeling-off and a crack of an insulating layer are hard to occur in the case bending work is applied to the insulated electric wire.

This is an insulated electric wire in which an electrodeposition covered film of block-copolymerized polyimide containing a siloxane bond in the main chain of the polyimide, and having an anionic group in a molecule is installed as the insulating layer of the outer periphery of a conductive wire. The insulated electric wire becomes the insulated electric wire which has superior heat resistance, in which the peeling-off and the crack of the insulating layer are hard to occur in the bending work of the electric wire, and which is superior in flexibility. In particular, as for the insulated electric wire in which a cross-sectional shape of the conductor wire is in a flat form, because the electrodeposition covered film is stably formed at a corner part of the outer periphery of the conductor wire, and because the thickness of the covered film to cover a flat part of the outer periphery of the conductor wire can be made thinner, the superior heat resistance, withstand voltage property, and working resistance of the insulating electric wire can be achieved, and downsizing (weight reduction) is realized.