To provide a mobile radio apparatus enabling an effective use of a communication channel by reducing a retransmission time. The mobile radio apparatus includes a transmitter for transmitting data to a transmission destination apparatus via a radio network; after the lapse of a predetermined time from the data transmission, a receiver for receiving from the transmission destination apparatus either a positive acknowledgement (ACK) indicative of normal data reception in the transmission destination apparatus, or a negative acknowledgement (NACK) indicative of abnormal data reception; and after the data transmission, a retransmission controller for retransmitting the data to the transmission destination apparatus before receiving either the positive acknowledgement or the negative acknowledgement for the data.