Every frame represented by a moving picture signal is divided into blocks. Calculation is made as to a number of pixels forming portions of a caption in each of the blocks. The calculated number of pixels is compared with a threshold value. When the calculated number of pixels is equal to or greater than the threshold value, it is decided that the related block is a caption-containing block. Detection is made as to a time interval related to the moving picture signal during which every frame represented by the moving picture signal has a caption-containing block. A 1-frame-corresponding segment of the moving picture signal is selected which represents a caption-added frame present in the detected time interval.