A power conversion apparatus for supplying an AC voltage to a motor determined for controlling a refrigeration cycle, comprising: a rectifier circuit configured to rectify an AC voltage from an AC power source; a booster circuit configured to boost an input voltage rectified by the rectifier circuit; a smoothing capacitor configured to smooth an output of the booster circuit; an inverter control unit configured to generate a PWM signal; an inverter circuit configured to convert a DC voltage smoothed by the smoothing capacitor into an AC voltage based on an input of the PWM signal and to supply the AC voltage to the motor; a boost mode switching unit having at least three boost modes, configured to switch among the a least three boost modes based on an input current from the rectifier circuit or a modulation factor of the PWM signal both of which change depending on an operation status of the motor; and a boost control unit configured to control the booster circuit based on the switching by the boost mode switching unit, characterized in that the boost mode switching unit is configured to select a boost level of the input voltage in each of the boost modes, wherein the at least three boost modes comprise a first boost mode in which a boost level is set lowest and higher than the input voltage, a second boost mode in which a boost level is set higher than the boost level in the first boost mode, and a third boost mode in which a boost level is set higher than the boost level in the second boost mode, and wherein the boost mode switching unit is configured to switch to the first boost mode when the booster circuit does not carry out boosting and when the input current from the rectifier circuit exceeds a threshold value A that is set in advance. a rectifier circuit configured to rectify an AC voltage from an AC power source; a booster circuit configured to boost an input voltage rectified by the rectifier circuit; a smoothing capacitor configured to smooth an output of the booster circuit; an inverter control unit configured to generate a PWM signal; an inverter circuit configured to convert a DC voltage smoothed by the smoothing capacitor into an AC voltage based on an input of the PWM signal and to supply the AC voltage to the motor; a boost mode switching unit having at least three boost modes, configured to switch among the a least three boost modes based on an input current from the rectifier circuit or a modulation factor of the PWM signal both of which change depending on an operation status of the motor; and a boost control unit configured to control the booster circuit based on the switching by the boost mode switching unit, characterized in that the boost mode switching unit is configured to select a boost level of the input voltage in each of the boost modes, wherein the at least three boost modes comprise a first boost mode in which a boost level is set lowest and higher than the input voltage, a second boost mode in which a boost level is set higher than the boost level in the first boost mode, and a third boost mode in which a boost level is set higher than the boost level in the second boost mode, and wherein the boost mode switching unit is configured to switch to the first boost mode when the booster circuit does not carry out boosting and when the input current from the rectifier circuit exceeds a threshold value A that is set in advance.