An apparatus for lapping a slider comprises a lapping head for supporting elements while pressing the elements against a rotating lapping plate, the elements that are to be formed into sliders, a holding mechanism for supporting the lapping head, the holding mechanism having a first engaging member that extends in a vertical direction, a base for supporting the holding mechanism, the base having a second engaging member that extends in the vertical direction, wherein the second engaging member is engaged with the first engaging member to form an internal space therebetween, and a decompressing mechanism for decompressing the internal space. The holding mechanism is subjected to vertically upward force from the decompressed internal space in order to be movably supported by the base in the vertical direction.