A printing apparatus is capable of being driven by a battery (20) for an extended period of time without using a battery having a large capacity, and the battery (20) is capable of being charged while the occurrence of the memory effect is suppressed. Also provided is a method of charging the battery (20) in this apparatus. Battery capacity is detected in the driving interval of a carriage motor (8) and/or conveyance motor (10). When the battery capacity falls below a predetermined value, control is performed in such a manner that the driving intervals of the carriage motor (8) and conveyance motor (10) will not overlap. When charging of the battery is designated, the battery (20) is discharged using a current load in the apparatus, after which the battery (20) is charged.