Abstract: According to one embodiment, a reproducing device of an information storage medium sufficiently reproduces resource data of advanced contents as much as possible. The device uses a ring buffer to temporarily store packets of resource data of a video stream. Packets read out from the buffer are basically transferred to a file cache in response to a playlist. If a storage area in the cache cannot be secured, a packet list storage unit stores a packet list to be stored in the buffer. The packet list includes a pointer on the buffer of packets composing the resource data. When the cache makes it possible to store the packets therein, the buffer can transfer the packets to the cache at a high speed.