The present invention is applied to imaging apparatuses including video cameras for recording moving pictures, electronic still cameras, monitoring devices and such. An image pickup means 3 and an image compressing means 5 are connected integrally by a wiring layer formed on a surface of the image pickup means 3 opposite a light-receiving surface of the image pickup means 3. The image pickup means 3 provides processing units of image data S1 relating to an image compressing process sequentially. Image data on a partial area in an effective image area is compressed to detect a code amount in advance. A data compressing ratio is determined on the basis of the code amount, and the image data is compressed at the image compressing ratio.