An oscillator includes a first VCXO and a second VCXO which are capable of changing an output frequency by application of a control voltage, and a control voltage terminal to which the control voltage is applied, the first VCXO includes a variable-capacitance diode (first variable-capacitance diode) and a resistor (first resistor), the second VCXO includes a variable-capacitance diode (second variable-capacitance diode) and a resistor (second resistor), the cutoff frequency of the first variable-capacitance diode, the second variable-capacitance diode, the first resistor, and the second resistor is equal to the cutoff frequency of the first variable-capacitance diode and the first resistor, and the cutoff frequency of the second variable-capacitance diode and the second resistor.