To enable a reduction in stress given to a patient by finishing positioning operations within a short time so as to shorten time for finishing all processes.

The distance between a top board 201, whereon a subject is placed, of a conveying device 200 and a scanning surface of a gantry device is stored in advance. A marker member 203 slidable in a conveying direction is installed near the top board 201 of the conveying device 200 and moved to a position to scan the subject, and instructions as to the completion of movement are given by an operation panel 202. Consequently, because the amount of conveyance of the top board 201 can be calculated based on the input distance of the marker member 203 and the distance to the gantry device, the top board 201 is conveyed according to those distances.