Provided is a flexible display device including a display body having flexibility; an actuator for changing and driving the display body; and an initial shape forming substrate for maintaining an initial state of the display body before the display body is changed and driven. The flexible display device allows a user to exactly control a change state of the flexible display device by driving the actuator and to decrease power consumption for changing and driving the flexible display device. Thus, by using the flexible display device, user convenience can be improved and the flexible display device can be driven with low power consumption.