Before start of vehicle charging by using a power network, a first determination unit determines whether reserve of the power network is not less than a first reference value. When reserve of the power network is not less than the first reference value, a first permission unit permits supply of electric power from the power network to a vehicle. When reserve of the power network is smaller than the first reference value, a second determination unit determines whether or not electric power corresponding to charging power can be supplied to the power network by having at least one of power adjustment resources respond to vehicle charging. When the second determination unit determines that electric power can be supplied, a second permission unit permits supply of electric power from the power network to the vehicle.