Insulated wire and rotating electrical machine

An insulated wire, comprising:

• at least one foamed insulating layer composed of a thermosetting resin having bubbles, directly or indirectly on an outer periphery of a conductor,
• wherein the thermosetting resin is selected from a polyamideimide resin, a polyimide resin, a polyamide resin, a polyetherimide resin, a polyesterimide resin, and a polyethersulfone resin,
• wherein the foamed insulating layer has a difference in a bubble density in a thickness direction thereof to be 3% or more, and
• wherein an average bubble diameter of the foamed insulating layer is 10 μm or less.