In an on-vehicle radio communication apparatus, when the battery is in a voltage discharging state, every time a predetermined period pases, a current consumption value is updated for the radio circuit by integrating the current consumption for steady operation of the radio circuit. In addition, every time an event occurs in the radio circuit, the current consumption value is updated for the radio circuit by integrating the current consumption for the event operation. If the current consumption value is greater than or equal to a predetermined threshold value, the operation is stopped.