A thin film deposition apparatus includes: a chamber configured to process a plurality of substrates; a plurality of heater members disposed to correspond to the substrates to heat the substrates; a plurality of lift pins configured to be elevated through the heater members and support lower surfaces of the substrates; a plurality of support plates on which lower ends of the lift pins are configured to be seated; a plurality of support columns coupled with and supporting the heater members; and a plurality of spray ports configured to supply a process gas to the substrates, wherein the support plates are mounted on a plurality of seats formed on at least one side of the chamber, and configured to be elevated together with the heater members when the heater members are elevated.