PORTABLE INFORMATION APPARATUS AND INFORMATION STORAGE MEDIUM

PROBLEM TO BE SOLVED: To provide an electronic book and a portable information apparatus and an information storage medium used for them capable of realizing a function such as rotation, expansion, shrinkage, and scroll of a map image via a user-friendly human interface.SOLUTION: An electronic book includes a display part capable of displaying a map image. According to an operation history of a finger brought into contact with the display part, an execution instruction and an operation variable for at least one operation among rotation, expansion, shrinkage, and scroll of the map image can be inputted at the same time. By a motion to separate two fingers from each other, an expansion instruction and an expansion variable of the map image can be inputted. By a motion to bring two fingers close to each other, a shrinkage instruction and a shrinkage variable of the map image can be inputted. By a motion to turn one finger around another finger, a rotation instruction and a rotation variable of the map image can be inputted.