An information radio transmission system is provided that enables provision of correct control information on the transmitting side irrespective of the error volume when an error occurs in communication data. Error volume measuring data string storage units that store an error volume measuring data string are provided in both a transmitting-side communication device that transmits data by radio transmission and a receiving-side communication device that receives data transmitted from the transmitting-side communication device. The receiving-side communication device has an error volume measuring unit that measures the error volume when transmitting data. An error volume measuring data string is added to data and the data is transmitted from the transmitting-side communication device. Having received this, in the receiving-side communication device, the error volume measuring unit compares the error volume measuring data transmitted from the transmitting-side communication device with an error volume measuring data string stored in an error volume measuring data string storage unit of the receiving-side communication device, thereby measuring the error volume.