An intra prediction method and a device using the intra prediction method are provided. The intra prediction method using a DC mode includes setting a bottom-right pixel to a DC-predicted value, interpolating the bottom-right pixel and an n-th top reference pixel to derive predicted values of an n-th column and interpolating the bottom-right pixel and an n-th left reference pixel to derive predicted values of an n-row, and performing bidirectional linear interpolation to derive predicted values of pixels included in a prediction unit other than the n-th row and the n-th column.