An information communication system comprising: a plurality of in-vehicle information collecting devices individually mounted on a plurality of vehicles; a center server configured to manage each of the plurality of in-vehicle information collecting devices as a communication target; and a roadside device, including a roadside device control unit and a wireless transmission/reception unit, the roadside device being configured to relay communication between each of the plurality of in-vehicle information collecting devices and the center server, wherein each of the in-vehicle information collecting devices includes an in-vehicle controller configured to transmit/receive information including vehicle information on each of the vehicles, to/from the center server via the communication unit, the center server includes a server controller configured to transmit/receive information to/from an in-vehicle controller of each of the in-vehicle information collecting devices via the communication unit, characterised in that the server controller, when receiving the vehicle information from each the in-vehicle controller, is configured to analyze the received vehicle information by determining if the received vehicle information contains data having a value outside of a range of a fixed value from an average data value or determining if the received vehicle information contains data within a range of deviation values of a parameter, generates data transmission speed information that defines a transmission speed of the vehicle information based on an analysis result, and transmits the generated data transmission speed information to each the in-vehicle controller, and each the in-vehicle controller is configured to control, when receiving the data transmission speed information from the server controller, a communication amount of the vehicle information to the server controller based on the received data transmission speed information. a plurality of in-vehicle information collecting devices individually mounted on a plurality of vehicles; a center server configured to manage each of the plurality of in-vehicle information collecting devices as a communication target; and a roadside device, including a roadside device control unit and a wireless transmission/reception unit, the roadside device being configured to relay communication between each of the plurality of in-vehicle information collecting devices and the center server, wherein each of the in-vehicle information collecting devices includes an in-vehicle controller configured to transmit/receive information including vehicle information on each of the vehicles, to/from the center server via the communication unit, the center server includes a server controller configured to transmit/receive information to/from an in-vehicle controller of each of the in-vehicle information collecting devices via the communication unit, characterised in that the server controller, when receiving the vehicle information from each the in-vehicle controller, is configured to analyze the received vehicle information by determining if the received vehicle information contains data having a value outside of a range of a fixed value from an average data value or determining if the received vehicle information contains data within a range of deviation values of a parameter, generates data transmission speed information that defines a transmission speed of the vehicle information based on an analysis result, and transmits the generated data transmission speed information to each the in-vehicle controller, and each the in-vehicle controller is configured to control, when receiving the data transmission speed information from the server controller, a communication amount of the vehicle information to the server controller based on the received data transmission speed information.