To provide a transfer device and its control method for transferring works, which are moving on a conveying device, liable to be damaged, and dislikes contamination, to a specified place at high accuracy.

A conveyor drive motor is started at S1 by a transfer device which is provided with a robot with a conveyor to transfer glass substrates linearly, a holding device to hold the glass substrates and transfer to a specified position, and a hand to suck and raise the glass substrates when they are held at its top end so as to move the glass substrates on a conveyor. When the glass substrates are detected by a sensor 15 (S2), the conveyor drive motor is stopped, the robot is moved in the direction opposite to the operating direction of the conveyor (S3 to S4) and, when the robot detects the sensor 18, the operation of the robot is stopped (S5 to S6). Through these operations, the positioning of the glass substrates relative to the robot hand is completed. Then a control device starts the transfer operation to a stage as the next process.