A unit wall coupling structure of a composite panel which prevents a fire from spreading due to an insulation material during a fire by simultaneously covering the exterior of the insulation material with mortar and bonding an ultra slim stone tile to a surface of the insulation material, which is a unit wall coupling structure using an exterior composite panel in which an insulation panel unit is combined with an ultra-slim stone panel, the structure comprising:
- a wall structure part;
- a vertical-horizontal frame structure;
- an insulation panel unit member;
- a panel fixing angle member;
- and
- a wall vertical connection member,
- wherein the vertical-horizontal frame structure includes a vertical bar and a horizontal bar formed as a quadrangular frame for installation of the composite panel outside a retaining wall, and
- the vertical bar includes an upper vertical bar and a lower vertical bar that are connected by an expansion joint at a portion at which an access floor is formed.