A method of manufacturing an electronic component minimizes the occurrence of voids and degradation of characteristics in a resin-sealed portion, while reducing the costs thereof. A sealing step for sealing surface acoustic wave elements by a sealing resin member formed from a resin film is performed by mounting the surface acoustic wave elements on a collective mounting substrate and the resin film in a bag with a gas-barrier property, and causing the resin film to infiltrate between the surface acoustic wave elements mounted on the reduce-pressured-packed collective mounting substrate to be hermetically sealed by the pressure difference between the inside and the outside of the bag.