A switch system includes a bidirectional switch, a first gate driver circuit, a second gate driver circuit, a control unit, a first decision unit, and a second decision unit. The bidirectional switch includes a first source, a second source, a first gate, and a second gate. The first decision unit determines, based on a voltage at the first gate and a first threshold voltage, a state of the first gate in a first period in which a signal to turn OFF the first gate is output from the control unit to the first gate driver circuit. The second decision unit determines, based on a voltage at the second gate and a second threshold voltage, a state of the second gate in a second period in which a signal to turn OFF the second gate is output from the control unit to the second gate driver circuit.