A server device includes a determination unit and a control unit. The determination unit determines the degree of congestion of a communication network on the basis of a difference between the time difference, between the transmission time and the reception time of sensor data transmitted from a gateway device to the server device, and the communication period of time taken in a state where congestion does not occur. The control unit determines a sensor device from which sensor data is collected and a sensor device in which collection of sensor data is withheld on the basis of the determination result of the degree of congestion of the communication network, and sends an instruction including the determined content to the gateway device.