To improve the detection accuracy of an operation for an object displayed on a display screen without corrupting display on the display screen.A navigation device 100 includes: an acceleration sensor 130 which measures an acceleration; a display control unit 202 which displays an object for receiving an instruction of processing on a display panel of a display unit; an operation determination unit 204 which detects an operation for an object 165; and a setting unit 203 which sets a reaction region 167 detectable as an operation for the object 165 by the operation determination unit 204. The setting unit 203 changes the range of the reaction region 167 according to the magnitude and direction of the acceleration measured by the acceleration sensor 130.