PURPOSE: To shorten the execution time for the next transfer command by checking the state of the transfer destination and forecasting the next transfer command and then moving the transfer mechanism to that place in advance.

CONSTITUTION: In the magnetic tape medium transfer mechanism having a transfer control part 1 for controlling a moving mechanism main body 3 for carrying specified magnetic tapes from a housing rack 8 for housing a large number of magnetic tapes 2 to plural drives 5-7 for performing write and read operations, a control program set in the transfer control part 1 possesses a control sequence for making the moving mechanism main body 3 standby in the position of a drive that is nearest to the read and write finishing time out of the plural drives 5-7.