A method of manufacturing a wiring board with a built-in electronic component including providing a first base material having a support body and a first metal foil detachably adhered on the support body, forming a connection terminal for mounting an electronic component on the first metal foil of the first base material by an additive method, mounting an electronic component to the connection terminal such that the electronic component is electrically connected to the connection terminal and mounted on the first base material, covering the electronic component with an insulative material structure having a hollow portion such that the electronic component is accommodated in the hollow portion of the insulative material structure after the mounting and detaching the support body from the first metal foil such that a substrate having the first base material and the insulative material structure is formed.