A video encoding method includes: when an inter prediction mode corresponds to a merge mode, checking for whether predetermined candidate adding conditions are satisfied; adding into a merge candidate set including merge candidates corresponding to neighboring blocks of a current block, a combined bi-predictive motion parameter, the combined bi-predictive motion parameter generated by combining a list 0 motion parameter of a first available candidate block and a list 1 motion parameter of a second available candidate block, when the predetermined candidate adding conditions are satisfied; and predicting the current block in the merge mode by using a motion parameter corresponding to a merge candidate selected from the merge candidate set, to generate a predicted block for the current block, wherein the merge candidate set corresponds to a maximum number of the merge candidates, the maximum number of the merge candidates corresponding to information on the number of the merge candidates.