Abstract: A data acquirer acquires data from another device and stores the data in a buffer. A communicator transmits the data stored in the buffer to a data collection server. A line state acquirer acquires information on a line (line state data) and accumulates and stores the acquired line state data in a line state storer. A transmission data amount determiner determines a data amount transmittable by one connection to the data collection server based on the line state data stored in the line state storer. A transmission schedule generator generates a transmission schedule for data based on a total amount of data stored in the buffer and the data amount transmittable by one connection. The communicator transmits data according to the transmission schedule.