A loading mechanism in a video cassette deck comprising a cassette moving mechanism 100 for moving a cassette receiving portion 200 between an initial location and a running location. The cassette moving mechanism 100 has a slide arm 120 horizontally slidably attached on one of a pair of wall portions 110 provided on both left and right sides of the cassette receiving portion 200, a driving portion for sliding the slide arm 120, a cassette driving gear 130 which is rotatably supported on the wall portion 110 to which the slide arm 120 is attached and which is connected to the cassette receiving portion 200 through a groove portion 112 formed in the wall portion 110, and a door arm 140 for transmitting the motion of the slide arm 120 to a door. The cassette loading mechanism is designed so that the door is opened before the cassette receiving portion 200 is moved when the cassette receiving portion 200 in the running location is moved into the initial location.