A method for manufacturing a multi-layer printed circuit board having a via, comprising: providing a substrate with a first conductive layer formed on at least one surface of the substrate; providing a laminate by pasting a heat-curable resin composition layer with a release substrate attached thereto or by sequentially laminating the heat-curable resin composition layer and the release substrate to the surface of the substrate on which the first conductive layer is formed; forming an electrical insulating layer on the substrate by heating the laminate comprising the substrate, the first conductive layer, the heat-curable resin composition layer, and the release substrate, and curing the heat-curable resin composition layer; forming a hole for a via in the electrical insulating layer and the release substrate by irradiating a laser from above the release substrate, peeling the release substrate from the electrical insulating layer after forming the hole; and forming a second conductive layer on the surface and in the hole of the electrical insulating layer after peeling the release substrate from the electrical insulating layer, wherein the second conductive layer is electrically connected to the first conductive layer, wherein, the release substrate is formed using a material having a glass transition temperature, the heat-curable resin composition layer contains no more than 7.0 wt% of a volatile component and is no more than 25 μm thick, and the curing of the heat-curable resin composition layer occurs at a temperature that is equal to or greater than the glass transition temperature, characterized in that the release substrate is at least 80 μm thick. providing a substrate with a first conductive layer formed on at least one surface of the substrate; providing a laminate by pasting a heat-curable resin composition layer with a release substrate attached thereto or by sequentially laminating the heat-curable resin composition layer and the release substrate to the surface of the substrate on which the first conductive layer is formed; forming an electrical insulating layer on the substrate by heating the laminate comprising the substrate, the first conductive layer, the heat-curable resin composition layer, and the release substrate, and curing the heat-curable resin composition layer; forming a hole for a via in the electrical insulating layer and the release substrate by irradiating a laser from above the release substrate, peeling the release substrate from the electrical insulating layer after forming the hole; and forming a second conductive layer on the surface and in the hole of the electrical insulating layer after peeling the release substrate from the electrical insulating layer, wherein the second conductive layer is electrically connected to the first conductive layer, wherein, the release substrate is formed using a material having a glass transition temperature, the heat-curable resin composition layer contains no more than 7.0 wt% of a volatile component and is no more than 25 μm thick, and the curing of the heat-curable resin composition layer occurs at a temperature that is equal to or greater than the glass transition temperature, characterized in that the release substrate is at least 80 μm thick.