According to one embodiment, an image generator converts an input video signal to first and second divided signals to be displayed in first and second areas on one screen. First and second divided signal controllers receive the first and second divided signals, adjust the signals, and output the adjusted signals. The preparation-complete detector includes first and second frame memory groups to sequentially store a divided signal for a plurality of frames. First divided signal controller determines whether preparation to output video signals for the left and right eyes is complete or not. And First divided signal controller changes a memory selection state for reading the video signals for the left and right eyes from the first and second memory groups based on the determination indicating whether the preparation for output is complete or not complete.