An image processing device comprises: a display part on which various types of screens are displayed; a manipulation detecting part for detecting an input by a user on the screen; a grouping part for classifying multiple screen parts contained in the screen into a group as a closed region by the screen part that is capable of receiving the same event and associating the same event with the group as the common event in the group; an event determining part for identifying the closed region where the user's input is detected and running only an operational event determining routine corresponding to the event associated with the group of the identified closed region of a plurality of operational event determining routines when the input is detected, thereby specifying the event corresponding to the user's input; and a controlling part for controlling operations based on the specified event.