A power supply device of an electrically driven injection molding machine for supplying electric power to a servo motor (SM1; SM2; SM3; SM4) for driving a member of the electrically driven injection molding machine, the power supply device comprising: an AC/DC converter; and a power accumulating device, wherein: the AC/DC converter is configured to convert an AC voltage into a DC voltage, which can be supplied to a servo amplifier (SA1; SA2; SA3; SA4) for driving the servo motor (SM1; SM2; SM3; SM4); the power accumulating device is coupled to a DC circuit of the AC/DC converter; the power accumulating device comprises a power accumulating circuit and a control circuit; the power accumulating circuit comprises a first loop circuit and a second loop circuit; the first loop circuit comprises a coil, a first switch circuit (SW 1) and a capacitor coupled in series between a positive terminal and a negative terminal; the second loop circuit comprises the coil and a second switch circuit (SW 2) coupled in series between the positive terminal and the negative terminal; the power accumulating device is configured to accumulate electric power supplied from the DC circuit in the capacitor, and when accepting a predetermined output request for a DC voltage for driving the member of the electrically driven injection molding machine, to supply the DC voltage to the DC circuit to thereby supply to the servo amplifier (SA1; SA2; SA3; SA4) the DC voltage that is higher than the DC voltage generated from the AC/DC converter. an AC/DC converter; and a power accumulating device, wherein: the AC/DC converter is configured to convert an AC voltage into a DC voltage, which can be supplied to a servo amplifier (SA1; SA2; SA3; SA4) for driving the servo motor (SM1; SM2; SM3; SM4); the power accumulating device is coupled to a DC circuit of the AC/DC converter; the power accumulating device comprises a power accumulating circuit and a control circuit; the power accumulating circuit comprises a first loop circuit and a second loop circuit; the first loop circuit comprises a coil, a first switch circuit (SW 1) and a capacitor coupled in series between a positive terminal and a negative terminal; the second loop circuit comprises the coil and a second switch circuit (SW 2) coupled in series between the positive terminal and the negative terminal; the power accumulating device is configured to accumulate electric power supplied from the DC circuit in the capacitor, and when accepting a predetermined output request for a DC voltage for driving the member of the electrically driven injection molding machine, to supply the DC voltage to the DC circuit to thereby supply to the servo amplifier (SA1; SA2; SA3; SA4) the DC voltage that is higher than the DC voltage generated from the AC/DC converter. the AC/DC converter is configured to convert an AC voltage into a DC voltage, which can be supplied to a servo amplifier (SA1; SA2; SA3; SA4) for driving the servo motor (SM1; SM2; SM3; SM4); the power accumulating device is coupled to a DC circuit of the AC/DC converter; the power accumulating device comprises a power accumulating circuit and a control circuit; the power accumulating circuit comprises a first loop circuit and a second loop circuit; the first loop circuit comprises a coil, a first switch circuit (SW 1) and a capacitor coupled in series between a positive terminal and a negative terminal; the second loop circuit comprises the coil and a second switch circuit (SW 2) coupled in series between the positive terminal and the negative terminal; the power accumulating device is configured to accumulate electric power supplied from the DC circuit in the capacitor, and when accepting a predetermined output request for a DC voltage for driving the member of the electrically driven injection molding machine, to supply the DC voltage to the DC circuit to thereby supply to the servo amplifier (SA1; SA2; SA3; SA4) the DC voltage that is higher than the DC voltage generated from the AC/DC converter.