A composite integrated circuit is formed by being molded with a mold resin, including
a seat member of a lead frame, a substrate attached on the seat member of the lead
frame, a heater element, and a temperature-restricted element. Here, the heater
element and the temperature-restricted element are mounted on the substrate. The
seat member of the lead frame includes a hollow member that is located under an
intermediate area between the heater element and the temperature-restricted element.