Abstract: A method and an apparatus for mounting: the method for bonding a plurality of objects to each other, comprising the steps of disposing, apart from each other, a first object, a second object and a holding means therefor, and a backup member having a reference positioning surface in this order, adjusting the parallelism of the second object or the holding means therefor relative to the reference positioning surface, adjusting the parallelism of the first object or the holding means therefor relative to the second object or the holding means therefor, bringing the first object into contact with the second object to temporarily bond both objects to each other, bringing the holding means for the second object into contact with the reference positioning surface of the backup member, and pressing both objects against each other for final bonding, whereby, finally, a highly reliable and accurate bonding state can be achieved.