The heat dissipation of a pickup is improved in an optical disc apparatus of a slot-in type.A unit cover 16 on a disc-facing side of a unit mechanism 6 includes a circumferential plate 21, a lever supporting plate 22, a disc guiding plate 23, a flexible printed circuit board holding plate 24, a reinforcing plate 25, a driving part covering plate 27, ventilating openings near sub guiding shaft 28, an extended notch near sub guiding shaft 30, an outer extended notch 31, and an extended notch near main guiding shaft 32. With this configuration, plenty of air flow induced by the rotation of a disc 5 can be introduced to a pickup 9 also through the unit cover 16, greatly improving heat dissipation capability.