An X-ray computed tomography (CT) apparatus having an X-ray tube emitting an X-ray, a detector detecting X-rays transmitted through a subject to be examined, and a bed on which said subject to be examined is placed, said X-ray CT apparatus reconstructing the image of the subject to be examined from a transmission data obtained by emitting X-rays to the subject to be examined. The X-ray computed tomography (CT) apparatus further having an input part, a scan controlling part, a detecting part, a memory part, a segmentation part, a biological-signal synchronization reconstructing part, a biological-signal asynchronization reconstructing part, and a combining part.