A calibration method, a calibration apparatus, and a program capable of estimating a degree of signal loss of an input signal supplied to an oscillator are provided. The calibration method includes: outputting an input signal to be input to an oscillator to be calibrated that includes a resonator and performs parametric oscillation, from a signal generator connected to the resonator via a transmission path while sweeping a frequency or a power of this input signal; acquiring distribution data of an intensity of a reflection signal based on measurement of the intensity of the reflection signal from the oscillator in response to the input signal; and estimating a degree of signal loss by comparing the distribution data acquired by the measurement with the distribution data theoretically obtained in which a value of the degree of the signal loss of the transmission path is assumed.