A method of manufacturing an electronic component module includes sealing a surface of an aggregate substrate on which a plurality of electronic components are mounted with a sealing resin and cutting boundary portions between electronic component modules from an outer surface of the sealing resin to a position at least partially through the aggregate substrate to form first grooves. A shield layer is formed by coating the outer surface of the sealing resin with a conductive resin and filling the first grooves with the conductive resin, and recesses are formed at positions on the shield layer where the first grooves are formed. The boundary portions between electronic component modules are cut along the corresponding recesses so that second grooves each having a width smaller than the width of a corresponding one of the recesses are formed, and the aggregate substrate is singulated into the individual electronic component modules.