An image coding method includes generating a prediction block using intra prediction mode or motion information, transforming residual signals generated using an original block and the prediction block to generate a transformed block, quantizing the transformed block using a quantization parameter to generate a quantized block, determining a scan pattern and applying the scan pattern to the quantized block to generate one-dimensional coefficient information, and entropy-coding the one-dimensional coefficient information, wherein a transform type used for transforming the residual signals of luma components is DCT-based integer transform if prediction mode is inter prediction, and a transform type used for transforming the residual signals of chroma components is a DCT-based integer transform.