Provided are a computed tomography device and a computed tomography method. The computed tomography device includes a gantry and an image processing processor. The gantry includes a light source for irradiating light, a detector disposed facing the light source and for receiving the light, and an arm for supporting the light source and the detector. The image processing processor receives a two-dimensional detection image for a subject from the detector. The image processing processor converts the received two-dimensional detection image to two-dimensional detection image data. The image processing processor generates three-dimensional reconstruction image data from the two-dimensional detection image data. A computed tomography device and a computed tomography method according to the inventive concept correct an error of a gantry movement path to provide a stable three-dimensional reconstruction image.