Disclosed is a portable communication device including a cover window, a display panel including an active area and an inactive area substantially surrounding the active area, the active area including a plurality of pixels and the inactive area including no pixels, a flexible substrate including a first portion connected with the display panel, and a second portion extended from the first portion and bent below a rear surface of the display panel; a display driver integrated circuit (DDI) disposed in the second portion of the flexible substrate, a sensing circuit disposed in the flexible substrate not to be overlapped with the DDI, a plurality of signal lines each electrically connected between the DDI and at least one pixel of the plurality of pixels, and configured to be used to transmit a signal from the DDI to the at least one pixel, and a sensing line disposed in the flexible substrate and the inactive area except the active area and including a first ending portion which is electrically connected with a power line, and a second ending portion which is electrically connected with at least one signal line of the plurality of signal lines via the sensing circuit.