A centralized voltage controller connected, via a communication network, to local voltage control units controlling voltage controllers, which are connected to a distribution line of a distribution system and control voltage of the distribution line, has: a voltage distribution determination unit calculating a controlled amount for each first voltage controller to be controlled among the plurality of voltage controllers, based on a measured value of voltage at each point of the distribution line; a tap position determination unit generating a command value to be given to each local voltage control unit based on the controlled amount; and a control state determination unit determining whether each voltage controller is a second voltage controller that fails to perform control according to the command value, and setting the voltage controllers except the second voltage controller to be the first voltage controller.