Provided is a video decoding method including acquiring simplified depth coding (SDC) mode information indicating whether an SDC mode for encoding a residual block of a prediction unit included in a coding unit of a depth image by using one residual DC component is applied to the coding unit, acquiring the residual DC component corresponding to the prediction unit of the coding unit to which the SDC mode is applied based on the SDC mode information, and reconstructing a current block of the coding unit by using the residual DC component and a reference block of the prediction unit.