A water-dispersed insulating varnish composition according to the present invention is characterized by being prepared by mixing a heat-curable resin that has at least two (meth)acryloyl groups per molecule, a polyfunctional vinyl monomer that can be dissolved in the heat-curable resin and has at least two (meth)acryloyl or allyl groups per molecule, an organic peroxide that serves as a reaction initiator, a surfactant that serves as a dispersant, and water together, and also characterized by not containing a mono-functional vinyl monomer having one reactive group. The water-dispersed insulating varnish composition according to the present invention generates a VOC in a remarkably small volume when used in the insulation treatment of a coil, can prevent the occurrence of crazing in a coil winding, the securing of electric insulation of the coil winding, the physical support of the coil winding, the prevention of generation of heat in the coil winding and the protection of the coil winding, and has a long usable time.