A window manufacturing apparatus includes a transporting table on which a target substrate is to be mounted, the transporting table including a first portion and a second portion having a greater thickness than the first portion, a plurality of suctioning ports on a suctioning table, the plurality of suctioning ports being configured to suction the target substrate, and an attachment device configured to attach a protective film to the target substrate suctioned to the suctioning table. In a state in which the target substrate mounted on the transporting table is suctioned to the suctioning table, the plurality of suctioning ports overlap the second portion of the transporting table and do not overlap the first portion of the transporting table in a plan view.