A conversion device which converts a DC voltage inputted from a DC power supply, to an AC voltage in a non-insulated manner and supplies the AC voltage to a load, the conversion device comprising: a filter circuit connected to the load and including an AC reactor and a first capacitor; a DC/AC conversion unit provided between the filter circuit and a DC bus; a second capacitor connected to the DC bus; a DC/DC conversion unit provided between the DC bus and the DC power supply and including a DC reactor; and a control unit configured to control the DC/AC conversion unit and the DC/DC conversion unit, characterized in that: the control unit is configured to obtain an AC reactor current command value (Igaci*) by calculating a difference between an output voltage command value (Sinwave) for supplying the AC voltage to the load and a value (Vgaco_lpf) obtained through a low-pass filter process applied to an output voltage detection value (Vgaco); inputting the calculated difference to a PI compensator; and adding an output of the PI compensator to a value obtained through a low-pass filter process applied to an output current detection value; determine duties of control for the DC/AC conversion unit and the DC/DC conversion unit by considering electric influences of the filter circuit, the second capacitor, and the DC reactor for the output voltage command value (Sinwave), based on the AC reactor current command value (Igaci*) and a DC reactor current command value (Igdc*), respectively, control the DC/DC conversion unit to convert the DC voltage into a DC bus voltage waveform alternately having a period of a pulsating current waveform corresponding to an absolute value of the AC voltage and a period of the DC voltage as a pulsating current minimum value, and control the DC/AC conversion unit to perform step-down operation during the period of the DC voltage and thus perform conversion into a waveform of the absolute value of the AC voltage corresponding to the period of the DC voltage, and also to perform polarity inversion per one pulsating current cycle. a filter circuit connected to the load and including an AC reactor and a first capacitor; a DC/AC conversion unit provided between the filter circuit and a DC bus; a second capacitor connected to the DC bus; a DC/DC conversion unit provided between the DC bus and the DC power supply and including a DC reactor; and a control unit configured to control the DC/AC conversion unit and the DC/DC conversion unit, characterized in that: the control unit is configured to obtain an AC reactor current command value (Igaci*) by calculating a difference between an output voltage command value (Sinwave) for supplying the AC voltage to the load and a value (Vgaco_lpf) obtained through a low-pass filter process applied to an output voltage detection value (Vgaco); inputting the calculated difference to a PI compensator; and adding an output of the PI compensator to a value obtained through a low-pass filter process applied to an output current detection value; determine duties of control for the DC/AC conversion unit and the DC/DC conversion unit by considering electric influences of the filter circuit, the second capacitor, and the DC reactor for the output voltage command value (Sinwave), based on the AC reactor current command value (Igaci*) and a DC reactor current command value (Igdc*), respectively, control the DC/DC conversion unit to convert the DC voltage into a DC bus voltage waveform alternately having a period of a pulsating current waveform corresponding to an absolute value of the AC voltage and a period of the DC voltage as a pulsating current minimum value, and control the DC/AC conversion unit to perform step-down operation during the period of the DC voltage and thus perform conversion into a waveform of the absolute value of the AC voltage corresponding to the period of the DC voltage, and also to perform polarity inversion per one pulsating current cycle. the control unit is configured to obtain an AC reactor current command value (Igaci*) by calculating a difference between an output voltage command value (Sinwave) for supplying the AC voltage to the load and a value (Vgaco_lpf) obtained through a low-pass filter process applied to an output voltage detection value (Vgaco); inputting the calculated difference to a PI compensator; and adding an output of the PI compensator to a value obtained through a low-pass filter process applied to an output current detection value; determine duties of control for the DC/AC conversion unit and the DC/DC conversion unit by considering electric influences of the filter circuit, the second capacitor, and the DC reactor for the output voltage command value (Sinwave), based on the AC reactor current command value (Igaci*) and a DC reactor current command value (Igdc*), respectively, control the DC/DC conversion unit to convert the DC voltage into a DC bus voltage waveform alternately having a period of a pulsating current waveform corresponding to an absolute value of the AC voltage and a period of the DC voltage as a pulsating current minimum value, and control the DC/AC conversion unit to perform step-down operation during the period of the DC voltage and thus perform conversion into a waveform of the absolute value of the AC voltage corresponding to the period of the DC voltage, and also to perform polarity inversion per one pulsating current cycle.