In a hybrid integrated circuit device that is a circuit device of the present invention, a conductive pattern including pads is formed on a surface of a substrate. A first pad is formed to be relatively large since a heat sink is mounted thereon. A second pad is a small pad to which a chip component or a small signal transistor is fixed. In the present invention, a plated film made of nickel is formed on a surface of the first pad. Therefore, the first pad and a solder never come into contact with each other. Thus, a Cu/Sn alloy layer having poor soldering properties is not generated but a Ni/Sn alloy layer having excellent soldering properties is generated. Consequently, occurrence of sink in the melted solder is suppressed.