Abstract: High-speed scrolling is performed when an operating dial 35 is rotated taking a central button member 36 as an axis, and low-speed scrolling when pushing either an upper button 42A or a lower button 42C by pushing the operating dial 35 in the direction of an axis of rotation. It is therefore possible to include information it is wished to view, in an appropriate manner within a display range of a screen, with fewer operations by appropriately changing over the speed of scrolling. In addition, as it is possible to operate the operating dial 35 for both high-speed scrolling and low-speed scrolling, when changing over the speed of scrolling, it is possible to change over the speed of scrolling in a straightforward manner without operating members other than the member that has been operated so far.