To provide a computer system capable of automatically executing processing desired by a user at each of plural optically designated battery residual power points.

A battery event setting part 11 shows a battery event information setting image on a display controlling part 12, receives battery residual power points designated according to the setting image and a battery event to be generated through an input controlling part 13 and stores them as battery event information in a setting table of a data storing part 14. Meanwhile, a battery residual power monitoring part 15 monitors the change of battery residual power all the time and transfers the battery residual power to an operation executing part 16 at the moment when the change is detected. Furthermore, the part 16 detects battery event information that makes the battery residual power a battery residual power point from the setting table and executes the battery event shown by the detected battery event information by using the part 12, a sound controlling part 17, etc.