To provide a charger capable of minimizing the damage on battery life of a mobile terminal connected to an on-vehicle device for charging the battery efficiently.

A charger includes: charging means (21, 22) for charging a battery of the mobile terminal; prediction charging time acquisition means (S14, S15) for acquiring a prediction charging time of the battery until the charging means reaches the standard charging amount assuming that the battery is charged with a prescribed charging capacity; prediction running time acquisition means (S16) for acquiring prediction running time when an own vehicle runs from the present position to the destination; time comparison means (S17) for comparing the prediction charging time and the prediction running time; and charging control means (S18, S19) for controlling the charging capacity to the battery of the charging means in accordance with the comparison result of the time comparison means.