A method of manufacturing a foam-insulated wire, which uses a porous solid, which is able to improve performance of a foam-insulated wire by controlling the dispersion of the void content of the insulation, and the foam-insulated wire manufactured thereby are provided. The method comprising the steps of: forming a film of coating on the conductor with a water-in-oil form emulsion (O/W-form emulsion); curing the oil layer in the film of coating of the water-in-oil form emulsion by polymerization; removing water droplets therefrom; and thereby forming an insulation layer of a porous solid on the conductor.