Provided is a semiconductor chip, such as an MMIC or the like having a Si semiconductor as a substrate, which has a low-loss transmission line, can be easily connected to a circuit board on which the semiconductor chip is to be mounted, and can ensure a stable GND potential. The semiconductor chip, i.e., a semiconductor chip (10) to be flip-chip mounted, is provided with a Si substrate (11), an integrated circuit (12) formed on the main surface of the Si substrate (11), a dielectric film (16) formed above the integrated circuit (12), and a grounding conductor film (17) formed on the upper surface of the dielectric film (16). The integrated circuit (12) includes a wiring layer (13a) composed of a signal line (15) which transmits signals from the integrated circuit (12), and the signal line (15), the dielectric film (16) and the conductor film (17) configure a microstrip line.