To display the cumulative used capacity and remaining capacity of a storage part for application programs(APs) at the time of installing an AP in a storage part.

This controller is composed of a storage medium 6 in which a control program and AP are stored, a storage part 2, a control part 1 for reading the control program and AP out of the storage medium 6 and installing the AP in the storage part based on the script language information of the control program, an install capacity table 61a in which the capacity of the AP is stored, a selection part for selecting any AP to be installed in the storage part 2, a calculation part for calculating the cumulative used capacity and remaining capacity of all the selected AP based on the capacity of application stored in the install capacity table 61a, and a display part 3 for displaying the calculated cumulative used capacity and remaining capacity of all the APs.