A voltage converting circuit comprising: a plurality of first capacitors (21, 22, 23) configured to be charged by a power source; a second capacitor, connected in parallel to the plurality of first capacitors (21, 22, 23), capable of being charged to a voltage equal to a voltage that is supplied to a load circuit; a plurality of switching circuits (71a, 71b, 72a, 72b, 73a, 73b), configured to correspond to the plurality of first capacitors (21, 22, 23) respectively, each switching circuit (71a, 71b, 72a, 72b, 73a, 73b) switches states of connection between its corresponding first capacitor (21, 22, 23) and the second capacitor; and a connection control circuit (5, 41, 42, 43) configured to sequentially connect the first capacitors (21, 22, 23) to the second capacitor through the corresponding switching circuits (71a, 71b, 72a, 72b, 73a, 73b) as charging voltages of the first capacitors (21, 22, 23) reach a predetermined connection voltage that is higher than a charging voltage of the second capacitor, and control a state of connection of each of the first capacitors (21, 22, 23) to the second capacitor so that the first capacitors (21, 22, 23) are not short-circuited with each other the voltage converting circuit characterized in that: the voltage converting circuit further comprising voltage monitoring circuits (31, 32, 33) configured to correspond to the first capacitors (21, 22, 23) respectively, each voltage monitoring circuit (31, 32, 33) monitors the charging voltage of its corresponding first capacitor (21, 22, 23), wherein the connection control circuit (5, 41, 42, 43) carries out connection control through the switching circuits (71a, 71b, 72a, 72b, 73a, 73b) in accordance with the charging voltages of the first capacitors (21, 22, 23) obtained by the voltage monitoring circuits (31, 32, 33). a plurality of first capacitors (21, 22, 23) configured to be charged by a power source; a second capacitor, connected in parallel to the plurality of first capacitors (21, 22, 23), capable of being charged to a voltage equal to a voltage that is supplied to a load circuit; a plurality of switching circuits (71a, 71b, 72a, 72b, 73a, 73b), configured to correspond to the plurality of first capacitors (21, 22, 23) respectively, each switching circuit (71a, 71b, 72a, 72b, 73a, 73b) switches states of connection between its corresponding first capacitor (21, 22, 23) and the second capacitor; and a connection control circuit (5, 41, 42, 43) configured to sequentially connect the first capacitors (21, 22, 23) to the second capacitor through the corresponding switching circuits (71a, 71b, 72a, 72b, 73a, 73b) as charging voltages of the first capacitors (21, 22, 23) reach a predetermined connection voltage that is higher than a charging voltage of the second capacitor, and control a state of connection of each of the first capacitors (21, 22, 23) to the second capacitor so that the first capacitors (21, 22, 23) are not short-circuited with each other the voltage converting circuit characterized in that: the voltage converting circuit further comprising voltage monitoring circuits (31, 32, 33) configured to correspond to the first capacitors (21, 22, 23) respectively, each voltage monitoring circuit (31, 32, 33) monitors the charging voltage of its corresponding first capacitor (21, 22, 23), wherein the connection control circuit (5, 41, 42, 43) carries out connection control through the switching circuits (71a, 71b, 72a, 72b, 73a, 73b) in accordance with the charging voltages of the first capacitors (21, 22, 23) obtained by the voltage monitoring circuits (31, 32, 33). the voltage converting circuit further comprising voltage monitoring circuits (31, 32, 33) configured to correspond to the first capacitors (21, 22, 23) respectively, each voltage monitoring circuit (31, 32, 33) monitors the charging voltage of its corresponding first capacitor (21, 22, 23), wherein the connection control circuit (5, 41, 42, 43) carries out connection control through the switching circuits (71a, 71b, 72a, 72b, 73a, 73b) in accordance with the charging voltages of the first capacitors (21, 22, 23) obtained by the voltage monitoring circuits (31, 32, 33).