The present invention is directed to an apparatus for processing substrates. This apparatus comprises: transfer means for transferring a plurality of substrates held in a horizontal attitude from a first carrier to a second carrier; turning means for turning the second carrier to thereby turn the plurality of substrates from the horizontal attitude to a vertical attitude; processing means for processing the plurality of substrates held in the vertical attitude; and a transport system for transporting the plurality of substrates held in the vertical attitude from the turning means to the processing means.