1. An imaging terminal comprising: an imaging unit which sequentially outputs original image data into which a light flux incident on an imaging area has been photoelectrically converted in a frame; an image processing unit which generates image data of a first image size from the original image data of a portion corresponding to a first area within the imaging area, and generates image data of a second image size from the original image data of a portion corresponding to a second area as a partial area within the first area; an extraction unit which extracts a part from the image data of the first image size and the image data of the second image size generated by the image processing unit in the frame; and an external interface which wirelessly sequentially transmits the image data of the first image size and the image data of the second image size extracted by the extraction unit, wherein the imaging unit includes an optical system having a focus lens which adjusts focus, and wherein the image processing unit sets the second image size to be larger than the first image size during driving of the focus lens.