In preferred embodiments, a method of manufacturing a hybrid integrated circuit device is provided, in which a plurality of circuit substrates 10 are manufactured from a single metal substrate 10A′ by dicing. In some embodiments, the method includes: preparing a metal substrate 10A′ having an insulating layer 11 formed on the top surface thereof; forming a plurality of conductive patterns 12 on the top surface of insulating layer 11; forming grooves 20 in lattice form on the rear surface of metal substrate 10B′; mounting hybrid integrated circuits onto conductive patterns 12; and separating individual circuit substrates 10 with, for example, a rotatable cutter.