A heat treatment apparatus configured to perform heat treatment on a wafer having a surface on which a coating film is formed, and includes: a holding member for holding the wafer almost horizontally; a chamber for housing the wafer held by the holding member; a hot plate having gas permeability and disposed above the wafer held by the holding member in the chamber so that the coating film formed on the wafer can be directly heated; and an exhaust port provided on the top face of the chamber and exhausting gas in the chamber. Gas generated from the coating film passes through the hot plate and is exhausted from the chamber. Accordingly, uniformity of a coating film is improved. As a result, CD uniformity may be improved, LER characteristics may be improved, and a smooth pattern side face may be obtained.