PROGRAM UPDATE METHOD

The invention provides a program updating method which can avoid control program updating failure caused by power shortage of a first storage battery (BAT1) and can update a control program as early as possible. An update control device (11) acquires the remaining capacity (X) of power of a first battery (BAT1) that supplies power to an electronic control device (12) for updating a control program (step S24); acquiring an electric quantity (Y) required by the electronic control device (12) to update the control program (step S25); when the remaining capacity (X) is less than the electric quantity (Y) (YES in step S26), charging the first storage battery (BAT1) so that the remaining capacity (X) becomes equal to or greater than the electric quantity (Y) (steps S32-34); then, the electronic control device (12) is made to update the control program (step S36). 本发明提供了一种能够避免由于第一蓄电池(BAT1)的电力不足而导致控制程序更新失败，并且能够尽早进行控制程序的更新的程序更新方法。更新控制装置(11)获取向用于更新控制程序的电子控制装置(12)供给电力的第一蓄电池(BAT1)的电力的剩余容量(X)(步骤S24)；获取电子控制装置(12)更新控制程序所需的电