The present disclosure aims to provide a method for detecting a GOP boundary of an encoded bit stream of each layer and associating GOPs of the layers for hierarchical transmission in a video transmission device that transmits a hierarchically encoded bit stream. The present disclosure provides a video transmission device and a video transmission method that detect a GOP head access unit in a base layer of a hierarchically encoded bit stream by analyzing the base layer and detect a head access unit of an enhancement layer of an identical GOP to that of the aforementioned access unit from a decoding time stamp of the access unit by using the relationship between a decoding time stamp of the base layer and a decoding time stamp of the enhancement layer.