A high-frequency switch (100; 200; 300) comprising: a first transistor having a drain terminal connected to an input terminal, and a source terminal connected to a first output terminal; a second transistor having a drain terminal connected to the first output terminal; a third transistor having a drain terminal connected to a source terminal of the second transistor, and a grounded source terminal; a resistor having one end connected to a connection between the source terminal of the second transistor and the drain terminal of the third transistor, and another end grounded; a switching circuit (6,8) connected between the input terminal and a second output terminal, the switching circuit being switchable between a state in which the switching circuit allows passage of a transmitted/received signal between the input terminal and the second output terminal and a state in which the switching circuit cuts off the transmitted/received signal; and a control unit to control the first transistor, the second transistor, the third transistor, and the switching circuit, wherein at a time of reception without an automatic gain control operation, the control unit brings the switching circuit into the state in which the switching circuit cuts off the transmitted/received signal, places the first transistor and the third transistor in an on-state, and places the second transistor in an off-state, and at a time of transmission and reception with the automatic gain control operation, the control unit brings the switching circuit into the state in which the switching circuit allows the passage of the transmitted/received signal, places the first transistor and the third transistor in an off-state, and places the second transistor in an on-state. a first transistor having a drain terminal connected to an input terminal, and a source terminal connected to a first output terminal; a second transistor having a drain terminal connected to the first output terminal; a third transistor having a drain terminal connected to a source terminal of the second transistor, and a grounded source terminal; a resistor having one end connected to a connection between the source terminal of the second transistor and the drain terminal of the third transistor, and another end grounded; a switching circuit (6,8) connected between the input terminal and a second output terminal, the switching circuit being switchable between a state in which the switching circuit allows passage of a transmitted/received signal between the input terminal and the second output terminal and a state in which the switching circuit cuts off the transmitted/received signal; and a control unit to control the first transistor, the second transistor, the third transistor, and the switching circuit, wherein at a time of reception without an automatic gain control operation, the control unit brings the switching circuit into the state in which the switching circuit cuts off the transmitted/received signal, places the first transistor and the third transistor in an on-state, and places the second transistor in an off-state, and at a time of transmission and reception with the automatic gain control operation, the control unit brings the switching circuit into the state in which the switching circuit allows the passage of the transmitted/received signal, places the first transistor and the third transistor in an off-state, and places the second transistor in an on-state.