Abstract: A base of an optical pickup includes a first bearing portion through which one of two guide shafts disposed in parallel to each other is inserted and a second bearing portion through which the other guide shaft is inserted, and is slidable along the two guide shafts. Under the first guide shaft that is inserted through the first bearing portion, a nut hold portion for holding a nut that connects a member of a drive mechanism for driving the base and the base to each other is disposed on the base. The nut hold portion includes an insertion opening that allows the nut to be inserted along a direction substantially parallel to a longitudinal direction of the first guide shaft.