A structure for easily connecting prefabricated panels, which are attached to outer and inner walls of buildings, is disclosed. The structure includes inner prefabricated panels (10), each of which has a recess (11) and a rib (12) at its upper end and has an inner rib (13) bent downward to be engaged in a recess of a lower adjacent panel; corner finishing members (20) provided at a corner between adjacent panels, and each of which has opposite wing portions (21); inner ribs (22) protruded inwardly and having claw portions (23) respectively; outer prefabricating panels (10-2) attached onto the inner prefabricated panels (10); connecting members interposed between the adjacent outer panels (10-2) to attach the outer panel (10-2) to the inner panel (10); side finishing members (40) provided at sides of the inner panels (10), upper finishing members (40) provided at sides of the inner panels (10), upper finishing members (40) provided at uppermost inner panel; and lower finishing member (60) provided at uppermost inner panel; and lower finishing member (60) provided at an lowermost inner panel.