PURPOSE: To provide a recording/reproducing device eliminating the need for precise attaching or positioning of a position detector and capable of moving a cassette holder by a motor.

CONSTITUTION: This device is provided with a cassette holder 10 movable between a loading position and an operation position by the motor 19 through a multi-stage transmission device 20, and the transmission member 27 of the transmission device is connected to a pulse generator 41 driven through the transmission device when a cassette 5 is inserted into the cassette holder manually, and the cassette holder is moved manually from the loading position to a switch position at this time, and the pulse generator generates a pulse counted by a counter 46, and a comparator 47 compares the count Z1 of the counter with a nominal value N1, and when the count Z1 coincides with the nominal value N1, though it is the case that the cassette holder arrives at the switch position, the comparator generates a control signal for the motor, and thereafter, the motor moves the cassette holder from the switch position to the operation position through the transmission device.