To provide a device for controlling bed for a medical diagnostic apparatus which does not cause troubles to a technician and is equipped with a controlling system to adjust a subject's imaging region to an imaging region for an imaging system easily within a short period of time.

A device for controlling bed is equipped with the following parts: A means to input the subject's body-build inputs the subject's height and a distance between imaging regions. A means to specify and input imaging regions specifies the subject's imaging region and inputs it. A means to detect position of table detects a position of a table to put the subject on. A means to detect position of bed detects a position of a bed supporting the table. A distance to move the table and the bed from the imaging region specified by the means to specify and input imaging regions to the imaging region for the imaging system is calculated using a current position of the bed and the table detected by the means to detect position of table and the means to detect position of bed and the subject's height and the distance between the imaging regions input from the means to input the subject's body-build. The position of the table and the bed is adjusted to the imaging region for the imaging system based on the calculated distance to move them.