According to one embodiment, a response time calculation unit (22) calculates a response time of each of the cars required when the car stop call is assigned to the car. An assignment control unit (23) assigns the car stop call to the optimum car, based on the response time of each of the cars. A car load calculation unit (24) calculates a load value of each car at the time when each car starts from a registration floor of the car stop call after responding to the call. A boarding possibility determination unit (25) determines, for each car, whether the user can get on the car or not, by comparing the load value with a preset capacity value. A registration control unit (21) performs control to assign the car stop call, including a second and later responses to the registration floor of the car stop call, based on a determination result of the boarding possibility.