A flexible display apparatus comprising: a flexible display comprising a front surface configured to display a screen; a sensor; and a controller configured to: in response to a bending of the flexible display being sensed by the sensor while the flexible display is in an inactivation state, activate, in a bending state of the flexible display, a region of the front surface of the flexible display among regions into which the front surface of the flexible display is divided based on the bending, and control, in the bending state of the flexible display, the flexible display to display an execution screen of a function corresponding to the activated region of the front surface of the flexible display on the activated region of the front surface of the flexible display and to maintain the other region of the front surface of the flexible display in the inactivation state, wherein the bending of the flexible display being sensed by the sensor comprises sensing that the region of the front surface of the flexible display is bent by more than a predetermined radius of curvature, wherein the inactivation state is a standby state; and wherein the controller is further configured to, in response to an unfolding of the region of the flexible display being sensed by the sensor, return, in the flat state of the flexible display, the entire flexible display to the inactivation state. a flexible display comprising a front surface configured to display a screen; a sensor; and a controller configured to: in response to a bending of the flexible display being sensed by the sensor while the flexible display is in an inactivation state, activate, in a bending state of the flexible display, a region of the front surface of the flexible display among regions into which the front surface of the flexible display is divided based on the bending, and control, in the bending state of the flexible display, the flexible display to display an execution screen of a function corresponding to the activated region of the front surface of the flexible display on the activated region of the front surface of the flexible display and to maintain the other region of the front surface of the flexible display in the inactivation state, wherein the bending of the flexible display being sensed by the sensor comprises sensing that the region of the front surface of the flexible display is bent by more than a predetermined radius of curvature, wherein the inactivation state is a standby state; and wherein the controller is further configured to, in response to an unfolding of the region of the flexible display being sensed by the sensor, return, in the flat state of the flexible display, the entire flexible display to the inactivation state. in response to a bending of the flexible display being sensed by the sensor while the flexible display is in an inactivation state, activate, in a bending state of the flexible display, a region of the front surface of the flexible display among regions into which the front surface of the flexible display is divided based on the bending, and control, in the bending state of the flexible display, the flexible display to display an execution screen of a function corresponding to the activated region of the front surface of the flexible display on the activated region of the front surface of the flexible display and to maintain the other region of the front surface of the flexible display in the inactivation state, wherein the bending of the flexible display being sensed by the sensor comprises sensing that the region of the front surface of the flexible display is bent by more than a predetermined radius of curvature, wherein the inactivation state is a standby state; and wherein the controller is further configured to, in response to an unfolding of the region of the flexible display being sensed by the sensor, return, in the flat state of the flexible display, the entire flexible display to the inactivation state.