Disclosed herein is a combined panoramic and computed tomography photographing apparatus. The apparatus includes, an X-ray light source part, an X-ray sensor part having a panoramic sensor and/or a CT sensor for detecting X-rays which are generated from the X-ray light source part and pass through an object, a rotary arm for arranging the X-ray light source part and the X-ray sensor part thereon in such a way as to be opposed to each other, a rotary arm supporting member, and rotary arm driving means, wherein a distance between the X-ray light source part and the X-ray sensor part arranged opposed to each other with respect to the rotary arm is variable. The apparatus can conduct all of panoramic photographing and CT photographing, and provide the optimum enlargement ratio according to whether the panoramic photographing or the CT photographing is conducted.