A disk drive unit for a disk includes a mounting plate, a spindle motor assembly, a slide mechanism provided with a slide, a pickup unit mounted on the slide, a first transmission member operatively connected with the slide, and a second transmission member. The first transmission member is positioned such that it is in engagement with the second transmission member when the pickup unit is in its read and/or write position, and such that the first transmission member is out of engagement with the second transmission member when the pickup unit is in its home position. In order to bring the first and second transmission members into engagement, the transmission members are provided with engagement members. As a result, a limit switch assembly is no longer necessary.