A panel assembly comprising: a frame panel (10, 1010) including a front surface (10a, 1010a), an upper surface (10b, 1010b), a side surface (10c, 1010c), and a rear surface formed from a single sheet of a metal plate; and a corner member (100, 1100) disposable in a gap (S, S1) formed between the upper surface (10b, 1010b) of the frame panel (10, 1010) and the side surface (10c, 1010c) of the frame panel (10, 1010), wherein the corner member (100, 1100) includes: an insertion member (no, 1110) insertable into the gap (S, S1) to fill the gap (S, S1); and a fixing member integrally formed with the insertion member (no, 1110) and disposed to be coupled to the rear surface of the frame panel (10, 1010) to fix the corner member (100, 1100) to the frame panel (10, 1010) when the insertion member (110, 1110) is inserted into the gap (S, S1), wherein the upper surface (10b, 1010b) and the side surface (10c, 1010c) are each bent from edges of the front surface (10a, 1010a), and the rear surface is formed by end portions bent from the upper surface (10b, 1010b) and the side surface (10c, 1010c) to face the front surface (10a, 1010a), characterized in that the fixing member includes a fixing surface in contact with the rear surface of the frame panel, and wherein the fixing surface of the fixing member includes a first coupling protrusion to be inserted into a first coupling opening (10-S1, 10-S2) formed on the rear surface of the frame panel (10, 1010) when the insertion member (110, 1110) is inserted into the gap (S, S1). a frame panel (10, 1010) including a front surface (10a, 1010a), an upper surface (10b, 1010b), a side surface (10c, 1010c), and a rear surface formed from a single sheet of a metal plate; and a corner member (100, 1100) disposable in a gap (S, S1) formed between the upper surface (10b, 1010b) of the frame panel (10, 1010) and the side surface (10c, 1010c) of the frame panel (10, 1010), wherein the corner member (100, 1100) includes: an insertion member (no, 1110) insertable into the gap (S, S1) to fill the gap (S, S1); and a fixing member integrally formed with the insertion member (no, 1110) and disposed to be coupled to the rear surface of the frame panel (10, 1010) to fix the corner member (100, 1100) to the frame panel (10, 1010) when the insertion member (110, 1110) is inserted into the gap (S, S1), wherein the upper surface (10b, 1010b) and the side surface (10c, 1010c) are each bent from edges of the front surface (10a, 1010a), and the rear surface is formed by end portions bent from the upper surface (10b, 1010b) and the side surface (10c, 1010c) to face the front surface (10a, 1010a), characterized in that the fixing member includes a fixing surface in contact with the rear surface of the frame panel, and wherein the fixing surface of the fixing member includes a first coupling protrusion to be inserted into a first coupling opening (10-S1, 10-S2) formed on the rear surface of the frame panel (10, 1010) when the insertion member (110, 1110) is inserted into the gap (S, S1). an insertion member (no, 1110) insertable into the gap (S, S1) to fill the gap (S, S1); and a fixing member integrally formed with the insertion member (no, 1110) and disposed to be coupled to the rear surface of the frame panel (10, 1010) to fix the corner member (100, 1100) to the frame panel (10, 1010) when the insertion member (110, 1110) is inserted into the gap (S, S1), wherein the upper surface (10b, 1010b) and the side surface (10c, 1010c) are each bent from edges of the front surface (10a, 1010a), and the rear surface is formed by end portions bent from the upper surface (10b, 1010b) and the side surface (10c, 1010c) to face the front surface (10a, 1010a), characterized in that the fixing member includes a fixing surface in contact with the rear surface of the frame panel, and wherein the fixing surface of the fixing member includes a first coupling protrusion to be inserted into a first coupling opening (10-S1, 10-S2) formed on the rear surface of the frame panel (10, 1010) when the insertion member (110, 1110) is inserted into the gap (S, S1).