1. An optical coherence tomography anterior eye part imaging apparatus, in which a tomographic image of an anterior eye part of subject's eye is obtained by an optical coherence tomography, the apparatus comprising: a tomographic image obtaining unit that is provided on an apparatus body mounted on a holder and obtains a tomographic image of subject's anterior eye part in a depth direction by the optical coherence tomography, the tomographic image being taken along a scan line; an imaging unit that is provided on the apparatus body to image a frontal image of the subject's eye; a display unit that displays the image of the subject's eye obtained by the imaging unit; a corneal apex location detecting unit that detects a location of a corneal apex of the subject's eye; an alignment unit that moves the apparatus body relative to the holder so that the location of the corneal apex corresponds with a predetermined image obtaining location; a designating unit that designates an area or a location whose tomographic image is to be obtained on the subject's frontal image displayed on the display unit; and a scan line setting unit that sets a scan line in the tomographic image obtaining unit on a straight line passing the corneal apex according to the area or location designated by the designating unit.