An assembling structure for a flat-panel display unit, comprising: a housing body comprised of a front cabinet and a rear cabinet is assembled to house a flat display panel; at both side faces of rear cabinet, several base portions that are extended by predetermined lengths toward the front cabinets from the both side faces are provided; at inner sides of side faces of the front cabinet, engaging portions for engaging the base portions are provided; at the base portions, protruding portions are provided; at the engaging portions, guides for allowing the protruding portions to be slid are formed at predetermined angles relative to a direction perpendicular to a display face of the flat display panel.