Abstract: A method for manufacturing an electronic device with a plurality of lead frames for individually supporting an electronic component 6 surrounded by a casing 8, which method includes the steps of charging a resin 10 into each casing 8 on a substrate 5 on which the plurality of supporting lead frames are disposed, and cutting the substrate 5 into individual lead frames. The step of charging the first resin includes the step of using a mask 1 that has through-holes 1a in positions corresponding to regions surrounded by the casings 8, to charge the resin 10 into the regions surrounded by the casings 8. The method is capable of improving the productivity of manufacturing electronic devices with lead frames for individually supporting an electronic component surrounded by a casing, and making the shape of the resin that covers the electronic components even.