Image data (still image data) is encoded to create video data. When an interval recording mode is set, a plurality of video data created by an encoder (image compressor 42) are merged, and the merged video data is recorded as a single interval video data. In the interval recording mode, power supply to the encoder is stopped every time an encoding process of the image data is completed. After the stop of the power supply to the encoder, the power supply to the encoder is resumed when an encoding process of the next image data needs to be performed. Continuity information is managed during the stop of the power supply to the encoder. The continuity information is necessary for creating the plurality of video data so that the interval video data constitutes a stream that can be reproduced continuously.