PURPOSE: To make it possible to switch from a screen before branch to a branch picture screen in a high speed by providing a buffer memory for projecting block information and a buffer memory for branch destination information.

CONSTITUTION: Assuming that a3n frame information of D3 block is prjected and branch is performed from a3n frame information to a3n+1 frame information or D0 block. After D3 block information is inputted to projecting block buffer memory BM2, the whole of frame information of next D4 block is inputted to buffer memory BM1 for branch destination. Then, a01 frame information of D0 block is inputted to buffer memory BM3 for branch destination. When projection advances to reach the branch point, information of a02 frame and after it of D0 block are loaded to projecting block buffer memory BM2, and D1block information is loaded to buffer memory BM1 for branch destination.