An inter prediction method by a decoding apparatus, the method comprising: receiving image information including a skip flag, a merge flag, prediction mode information and partition type information; checking the skip flag representing whether a skip mode is applied for a current coding unit; checking the prediction mode information representing whether an inter prediction or an intra prediction is performed and the partition type information representing a partition type for the current coding unit, based on a value of the skip flag being 0, wherein the value of the skip flag being 0 represents that the skip mode is not applied for the current coding unit; checking the merge flag representing whether a merge mode is applied to a prediction unit which is derived from the current coding unit based on the partition type information, based on the value of the skip flag being 0 and the prediction mode information representing that the inter prediction is performed for the current coding unit; and performing the inter prediction on the prediction unit based on a value of the merge flag, wherein the skip flag is checked by the decoding apparatus before checking of the merge flag by the decoding apparatus, wherein the partition type information and the prediction mode information are checked by the decoding apparatus before checking of the merge flag by the decoding apparatus, wherein the partition type for the inter prediction is one of partition types comprising a 2Nx2N partition type, a 2NxN partition type, and a Nx2N partition type, wherein the partition type information represents the partition type for the inter prediction of the current coding unit based on a binary code, wherein the binary code for the 2N x 2N partition type is "1", the binary code for the 2N x N partition type is "01", and the binary code for the N x 2N partition type is "001", and wherein the skip flag is signaled at a coding unit level, and the merge flag is signaled at a prediction unit level. receiving image information including a skip flag, a merge flag, prediction mode information and partition type information; checking the skip flag representing whether a skip mode is applied for a current coding unit; checking the prediction mode information representing whether an inter prediction or an intra prediction is performed and the partition type information representing a partition type for the current coding unit, based on a value of the skip flag being 0, wherein the value of the skip flag being 0 represents that the skip mode is not applied for the current coding unit; checking the merge flag representing whether a merge mode is applied to a prediction unit which is derived from the current coding unit based on the partition type information, based on the value of the skip flag being 0 and the prediction mode information representing that the inter prediction is performed for the current coding unit; and performing the inter prediction on the prediction unit based on a value of the merge flag, wherein the skip flag is checked by the decoding apparatus before checking of the merge flag by the decoding apparatus, wherein the partition type information and the prediction mode information are checked by the decoding apparatus before checking of the merge flag by the decoding apparatus, wherein the partition type for the inter prediction is one of partition types comprising a 2Nx2N partition type, a 2NxN partition type, and a Nx2N partition type, wherein the partition type information represents the partition type for the inter prediction of the current coding unit based on a binary code, wherein the binary code for the 2N x 2N partition type is "1", the binary code for the 2N x N partition type is "01", and the binary code for the N x 2N partition type is "001", and wherein the skip flag is signaled at a coding unit level, and the merge flag is signaled at a prediction unit level.