A multilayer insulated wire has a conductor and two or more extrusion-insulating layers to cover the conductor, wherein at least one layer of the insulating layers other than an innermost layer is formed by a resin mixture containing a polyphenylene sulfide resin (A) as a continuous phase and an olefin-based copolymer ingredient (B) as a dispersed phase, or wherein at least one layer of the insulating layers other than an innermost layer is formed by a resin mixture containing a polyphenylene sulfide resin (A) as a continuous phase, and an olefin-based copolymer ingredient (B) and a polyamide (E) as a dispersed phase; a transformer is made by the multilayer insulated wire.