The present invention provides a substrate treating method including the steps of joining a one-side surface of a substrate to be treated to a support substrate, treating the substrate to be treated in the condition where the substrate to be treated is supported by the support substrate, and removing the support substrate from the substrate to be treated. The step of joining the substrate to be treated to the support substrate includes melting a joint bump formed on the substrate to be treated so as to join the substrate to be treated to the support substrate, and the step of removing the support substrate from the substrate to be treated includes polishing the support substrate so as to remove the support substrate.