An inter prediction method comprising: judging whether or not a reference picture list of a candidate unit among reconstructed neighboring units and a reference picture list of a decoding target unit are the same as each other; selecting the candidate unit among reconstructed neighboring units if the reference picture list of the candidate unit among reconstructed neighboring units and the reference picture list of the decoding target unit are the same as each other; judging whether or not a motion information of the candidate unit among reconstructed neighboring units and a motion information of the decoding target unit are similar to each other, wherein: the motion information comprises at least one of a reference picture list, a reference picture index, a prediction direction, and a motion vector predictor; and the motion information of the candidate unit comprises a motion vector for motion vector prediction of the decoding target unit; and if the candidate unit among reconstructed neighboring units and the decoding target unit have different reference picture lists but use the same reference picture, judging that the motion information of the candidate unit among reconstructed neighboring units and of the decoding target unit are similar to each other; and selecting the candidate unit among reconstructed neighboring units if the motion information of the candidate unit among reconstructed neighboring units and the motion information of the decoding target unit are similar to each other; generating a candidate set for the decoding target unit using the selected candidate unit; and performing inter prediction on the decoding target unit using the generated candidate set and an encoding parameter identifier, the encoding parameter identifier specifying a motion vector of a reference unit, which is used for the inter prediction of the decoding target unit, from the candidate set. judging whether or not a reference picture list of a candidate unit among reconstructed neighboring units and a reference picture list of a decoding target unit are the same as each other; selecting the candidate unit among reconstructed neighboring units if the reference picture list of the candidate unit among reconstructed neighboring units and the reference picture list of the decoding target unit are the same as each other; judging whether or not a motion information of the candidate unit among reconstructed neighboring units and a motion information of the decoding target unit are similar to each other, wherein: the motion information comprises at least one of a reference picture list, a reference picture index, a prediction direction, and a motion vector predictor; and the motion information of the candidate unit comprises a motion vector for motion vector prediction of the decoding target unit; and if the candidate unit among reconstructed neighboring units and the decoding target unit have different reference picture lists but use the same reference picture, judging that the motion information of the candidate unit among reconstructed neighboring units and of the decoding target unit are similar to each other; and the motion information comprises at least one of a reference picture list, a reference picture index, a prediction direction, and a motion vector predictor; and the motion information of the candidate unit comprises a motion vector for motion vector prediction of the decoding target unit; and if the candidate unit among reconstructed neighboring units and the decoding target unit have different reference picture lists but use the same reference picture, judging that the motion information of the candidate unit among reconstructed neighboring units and of the decoding target unit are similar to each other; and selecting the candidate unit among reconstructed neighboring units if the motion information of the candidate unit among reconstructed neighboring units and the motion information of the decoding target unit are similar to each other; generating a candidate set for the decoding target unit using the selected candidate unit; and performing inter prediction on the decoding target unit using the generated candidate set and an encoding parameter identifier, the encoding parameter identifier specifying a motion vector of a reference unit, which is used for the inter prediction of the decoding target unit, from the candidate set.