A film forming apparatus comprising: a rotation shaft; a rotation stage provided on the rotation shaft, fixed to the rotation shaft, and configured to hold a plurality of workpieces on a plurality of placing areas disposed in a circumferential direction with respect to a central axis of the rotation shaft; a susceptor configured to provide a first opening and a second opening to face each other along a second direction that is orthogonal to a first direction parallel with the central axis, and provide an inner space between the first opening and the second opening so as to accommodate the rotation stage therein; a gas supply mechanism configured to form a gas flow from the first opening to the second opening through the inner space; a container configured to accommodate the susceptor; and a heating mechanism provided around the container and configured to heat the susceptor, wherein the susceptor includes a first wall portion and a second wall portion facing each other, the rotation stage is provided between the first wall portion and the second wall portion, the first wall portion faces the plurality of placing areas, and a first through hole through which the rotation shaft passes is formed in the second wall portion, characterised in that the second wall portion includes an intermediate area defined by a first circle having a first radius with respect to the central axis and a second circle having a second radius that is larger than the first radius with respect to the central axis, and the first radius is larger than a minimum distance between the central axis and each of the plurality of placing areas and the second radius is smaller than a maximum distance between the central axis and each of the plurality of the placing areas, and one or more of second through holes are formed in the intermediate area. a rotation shaft; a rotation stage provided on the rotation shaft, fixed to the rotation shaft, and configured to hold a plurality of workpieces on a plurality of placing areas disposed in a circumferential direction with respect to a central axis of the rotation shaft; a susceptor configured to provide a first opening and a second opening to face each other along a second direction that is orthogonal to a first direction parallel with the central axis, and provide an inner space between the first opening and the second opening so as to accommodate the rotation stage therein; a gas supply mechanism configured to form a gas flow from the first opening to the second opening through the inner space; a container configured to accommodate the susceptor; and a heating mechanism provided around the container and configured to heat the susceptor, wherein the susceptor includes a first wall portion and a second wall portion facing each other, the rotation stage is provided between the first wall portion and the second wall portion, the first wall portion faces the plurality of placing areas, and a first through hole through which the rotation shaft passes is formed in the second wall portion, characterised in that the second wall portion includes an intermediate area defined by a first circle having a first radius with respect to the central axis and a second circle having a second radius that is larger than the first radius with respect to the central axis, and the first radius is larger than a minimum distance between the central axis and each of the plurality of placing areas and the second radius is smaller than a maximum distance between the central axis and each of the plurality of the placing areas, and one or more of second through holes are formed in the intermediate area.