A mobile terminal device includes: a display; a display control module which displays an execution screen for an application program on the display; and a detection module which detects a posture of the mobile terminal device based on a gravity acceleration applied to the mobile terminal device. In this arrangement, the display control module controls a display direction of the execution screen with respect to the mobile terminal device according to the posture of the mobile terminal device, and performs suppression control so as to, even if the posture of the mobile terminal device is changed, suppress switching of the display direction corresponding to the changed posture, provided that a suppression condition for suppressing switching of the display direction is satisfied while the execution screen is displayed on the display.