An oscillation signal generation circuit comprising: an oscillator including: a reference signal source circuit that has a reference signal source outputting a reference signal and which, in operation, converts the output reference signal into a control voltage, a first filter that includes a variable resistance and a capacitance and which, in operation, removes noise in the control voltage, a first transistor which, in operation, converts the control voltage output from the first filter into a control current and outputs the control current, a core circuit which, in operation, is driven by the control current and generates an output signal, and an output terminal which, in operation, outputs the generated output signal; and a calibration circuit connected to the output terminal of the oscillator, which, in operation, detects whether or not the generated output signal is oscillating, and adjusts a current value of the control current by controlling a resistance value of the variable resistance in accordance with the detection result; characterized in that the calibration circuit adjusts the current value of the control current by changing an output value of the reference signal stepwise from a lower limit value to an upper limit value of a first range until the calibration circuit detects oscillation of the output signal, and if the calibration circuit does not detect the oscillation of the output signal even when the calibration circuit changes the output value of the reference signal to the upper limit value of the first range, the calibration circuit changes the resistance value of the variable resistance stepwise from an upper limit value to a lower limit value of a second range until the calibration circuit detects the oscillation of the output signal. an oscillator including: a reference signal source circuit that has a reference signal source outputting a reference signal and which, in operation, converts the output reference signal into a control voltage, a first filter that includes a variable resistance and a capacitance and which, in operation, removes noise in the control voltage, a first transistor which, in operation, converts the control voltage output from the first filter into a control current and outputs the control current, a core circuit which, in operation, is driven by the control current and generates an output signal, and an output terminal which, in operation, outputs the generated output signal; and a reference signal source circuit that has a reference signal source outputting a reference signal and which, in operation, converts the output reference signal into a control voltage, a first filter that includes a variable resistance and a capacitance and which, in operation, removes noise in the control voltage, a first transistor which, in operation, converts the control voltage output from the first filter into a control current and outputs the control current, a core circuit which, in operation, is driven by the control current and generates an output signal, and an output terminal which, in operation, outputs the generated output signal; and a calibration circuit connected to the output terminal of the oscillator, which, in operation, detects whether or not the generated output signal is oscillating, and adjusts a current value of the control current by controlling a resistance value of the variable resistance in accordance with the detection result; characterized in that the calibration circuit adjusts the current value of the control current by changing an output value of the reference signal stepwise from a lower limit value to an upper limit value of a first range until the calibration circuit detects oscillation of the output signal, and if the calibration circuit does not detect the oscillation of the output signal even when the calibration circuit changes the output value of the reference signal to the upper limit value of the first range, the calibration circuit changes the resistance value of the variable resistance stepwise from an upper limit value to a lower limit value of a second range until the calibration circuit detects the oscillation of the output signal.