A peeling device for peeling off a substrate to be processed and a support substrate from an overlapped substrate, the overlapped substrate being formed by bonding the substrate to be processed and the support substrate by an adhesive, which includes: a first holding unit configured to heat the substrate to be processed and configured to hold the substrate to be processed; a second holding unit configured to heat the support substrate and configured to hold the support substrate; a moving mechanism configured to horizontally move at least one of the first holding unit and the second holding unit relative to each other; and an inert gas supply mechanism configured to supply an inert gas onto a bonding surface of the substrate to be processed or a bonding surface of the support substrate.