A high-frequency circuit comprising first and second antenna terminals, a transmitting terminal and first and second receiving terminals for first and second communications systems, and first and second switch circuits each having a common terminal and at least first and second switching terminals; the first antenna terminal being connected to a common terminal of the first switch circuit, the transmitting terminal for the first communications system being connected to the first switching terminal of the first switch circuit, the second antenna terminal being connected to a common terminal of the second switch circuit, the transmitting terminal for the second communications system being connected to the first switching terminal of the second switch circuit, each first receiving terminal for the first and second communications systems being connected to the second switching terminal of the first switch circuit via a first receiving-side multiplexer circuit, each second receiving terminal for the first and second communications systems being connected to the second switching terminal of the second switch circuit via a second receiving-side multiplexer circuit.