A video decoding method comprising: obtaining, from a bitstream, split information indicating whether a current block is to be split into at least two lower blocks; when the split information indicates that the current block is not to be split into at least two lower blocks, decoding the current block based on encoding information about the current block; when the split information indicates that the current block is to be split into at least two lower blocks, splitting the current block into the at least two lower blocks, obtaining, from the bitstream, encoding order information indicating an encoding order of a left lower block and a right lower block among horizontally neighboring lower blocks among the at least two lower blocks, determining, based on the encoding order information, whether a decoding order of the left lower block and the right lower block is a first order from the left lower block to the right lower block or a second order from the right lower block to the left lower block; and decoding the left lower block and the right lower block according to the first order or the second order, characterized in that the decoding the left lower block and the right lower block according to the first order or the second order comprises: when the right lower block is decoded prior to the left lower block according to the second order, determining context information for prediction mode information of the left lower block by using whether a block adjacent to a left side of the left lower block is predicted in an intra mode, whether the right lower block adjacent to a right side of the left lower block is predicted in an intra mode, and whether a block adjacent to an upper side of the left lower block is predicted in an intra mode; performing entropy decoding by using the context information to obtain the prediction mode information of the left lower block; and performing prediction on the left lower block in a prediction mode determined based on the prediction mode information, among an intra mode or an inter mode. obtaining, from a bitstream, split information indicating whether a current block is to be split into at least two lower blocks; when the split information indicates that the current block is not to be split into at least two lower blocks, decoding the current block based on encoding information about the current block; when the split information indicates that the current block is to be split into at least two lower blocks, splitting the current block into the at least two lower blocks, obtaining, from the bitstream, encoding order information indicating an encoding order of a left lower block and a right lower block among horizontally neighboring lower blocks among the at least two lower blocks, determining, based on the encoding order information, whether a decoding order of the left lower block and the right lower block is a first order from the left lower block to the right lower block or a second order from the right lower block to the left lower block; and decoding the left lower block and the right lower block according to the first order or the second order, characterized in that the decoding the left lower block and the right lower block according to the first order or the second order comprises: when the right lower block is decoded prior to the left lower block according to the second order, determining context information for prediction mode information of the left lower block by using whether a block adjacent to a left side of the left lower block is predicted in an intra mode, whether the right lower block adjacent to a right side of the left lower block is predicted in an intra mode, and whether a block adjacent to an upper side of the left lower block is predicted in an intra mode; performing entropy decoding by using the context information to obtain the prediction mode information of the left lower block; and performing prediction on the left lower block in a prediction mode determined based on the prediction mode information, among an intra mode or an inter mode. when the right lower block is decoded prior to the left lower block according to the second order, determining context information for prediction mode information of the left lower block by using whether a block adjacent to a left side of the left lower block is predicted in an intra mode, whether the right lower block adjacent to a right side of the left lower block is predicted in an intra mode, and whether a block adjacent to an upper side of the left lower block is predicted in an intra mode; performing entropy decoding by using the context information to obtain the prediction mode information of the left lower block; and performing prediction on the left lower block in a prediction mode determined based on the prediction mode information, among an intra mode or an inter mode.