A method and apparatus for renewing software in a software-controlled machine is provided wherein a sensor (16) detects external command information to shift an operation control circuit (50) from an operating mode to a renewal mode, and then detects external operating data on software to store same from the sensor (16) in a program memory (53) of the renewal mode for easy renewal of the software in accordance with renewal control program. Then, the operation control circuit (50) is shifted from the renewal mode to the operating mode to operate the machine with the renewed operating data.