In a flat panel display device, in which a display panel 1 loosely fitted on a main surface of a chassis 4 and circuit substrates held in hook portions provided on side surfaces of the chassis are connected each other through TCP's by bending the latter TCP's, and a method for manufacturing the same device, a main slit for a rounded portion of each TCP is formed in a rounded portion of the TCP and an auxiliary sub slit is also formed adjacent to the main slit. In order to reduce the peeling force exerted on connecting/fixing portions between the TCP's and the display panel, the circuit substrate is pulled up by bending the main and sub slits and then returning the sub slit to a flat state to insert the circuit substrate into the hook portions.