Provided is a base station device that is mounted in a flying object, forms a communication area on a ground, establishes a communication connection with a user terminal in the communication area, and provides a radio communication service to the user terminal, and comprises a connection control unit that, when the number of connected terminals is larger than a first threshold, performs admission control in response to a connection request received from the user terminal, and when the number of connected terminals is smaller than the first threshold and larger than a second threshold smaller than the first threshold, periodically selects a connection allowable group, executes a connection establishment process in response to a connection request from a user terminal included in the connection allowable group, and executes a request rejection process that rejects a connection request from a user terminal not included in the connection allowable group.