In a cassette loading apparatus for a video tape recorder equipped with a front loading mechanism, bearing portions (45, 46) of a worm (10) are disposed at predetermined positions of side brackets (2, 3) for supporting a cassette holder (12) which have L-shaped guide holes (2a, 2b) for guiding the support shaft (12a) of the cassette holder in both horizontal and vertical directions, a reference hole (57) is bored on the base (53) of the video tape recorder, the shaft (10a) of the worm (10) is inserted through the bearing portions (45, 46) and the reference hole (57), and the worm shaft (10a) keeps constant the axial distance be­tween gears (8, 9) for a cassette loading mechanism and a driving gear (35) for driving the video tape recorder.