According to an embodiment, a video encoding method includes: determining whether it is possible to include an intra merge candidate in a merge candidate list; when it is possible to include the intra merge candidate in the merge candidate list, determining a merge candidate list including at least one of the intra merge candidate and an intra merge candidate of a current block; generating prediction samples of the current block by using a prediction candidate selected from the determined merge candidate list; and reconstructing the current block by using residual samples between the current blocks and the prediction samples of the current block.