To easily manufacturing a semiconductor high-frequency integrated circuit through the manufacturing process of conventional MMIC and eliminate the leakage of a signal flowing to a signal line.

A semiconductor high-frequency integrated circuit is provided with a semiconductor substrate (substrate 1) with an integrated circuit (FET 25) consisting of active and passive elements, an interlayer insulation film, a first signal line (drain electrode 7d) that is provided on the interlayer insulation film and is connected to the integrated circuit, a second signal line (signal line 7sw) that is provided on the interlayer insulation film, while an end part is provided while being separated from the end part of the drain electrode 7d by a specific interval, and a switch means (micromachine switch 24) for controlling the conduction/non conduction between first and second signal lines.