A high frequency device includes a base plate having a main surface, a dielectric on the main surface, along a first side of the base plate, a signal line on the dielectric and extending from the first side toward a central portion of the main surface, an island pattern of a metal on the dielectric, a metal frame having a contact portion contacting the main surface and a bridge portion on the signal line and the island pattern, together enclosing the central portion, a lead frame connected to an outside signal line of the signal line and which is located outside the metal frame, a semiconductor chip secured to the central portion, and a wire connecting the semiconductor chip to an inside signal line of the signal line and which is enclosed within the metal frame.