A managing station comprises a delay time measuring unit that measures, while transmitting a delay time measurement frame to each of the slave stations and receiving a response frame responsive to the delay time measurement frame from the slave station, an elapsed time from when transmitting the delay time measurement frame to when receiving the response frame and that calculates a delay time of the slave station; and a delay detecting unit that compares the calculated delay time and a delay judgment value that is an average of the delay times calculated in a past for the slave station to determine whether delay is occurring in the slave station for each of the slave stations and that identifies, if delay is occurring in the slave station, the position of a delay element using connection configuration information indicating connection states between the communication apparatuses in the network.