An inter-layer video decoding method includes searching for a neighboring block candidate which neighbors a current block and has a motion vector in an inter-layer direction, from among spatial and temporal neighboring block candidates; when the neighboring block candidate having the motion vector in the inter-layer direction is found, setting the motion vector in the inter-layer direction of the found neighboring block candidate as a disparity vector of the current block; when the neighboring block candidate having the motion vector in the inter-layer direction is not found, searching for a neighboring block candidate having disparity vector information from among the spatial and temporal neighboring block candidates; and when the neighboring block candidate having the disparity vector information is found, predicting a disparity vector of the current block based on the disparity vector information of the found candidate.