To solve the problem that a circuit device in which a circuit element is mounted on a ceramic substrate, a flexible sheet or the like used as a support substrate is reduced in size and thickness, a method for manufacturing the circuit device having high mass productivity is not established.

The method for manufacturing the circuit device comprises the steps of half scribing a surface of a conductive foil 60, and forming a separating groove 61. The method further comprises the steps of half scribing a rear surface of the foil 60 having a residual thick part of the groove 61 after the steps of die bonding, wire bonding and epoxy coating, and removing the foil 60. Thus, an electric isolation of a conductive pattern can be executed by a scribing facility.