Film forming apparatus

A film forming apparatus comprising:

• a reaction chamber configured to enable a reaction on a substrate;
• and
• a supply part placed above the reaction chamber and configured to supply at least a first gas and a second gas onto the substrate, wherein
• the supply part comprises
• a first partition,
• a second partition provided under the first partition at a predetermined interval therefrom,
• a third partition provided under the second partition at a predetermined interval therefrom,
• a first flow path provided between the first partition and the second partition to allow the first gas to be introduced therein,
• a second flow path provided between the second partition and the third partition to allow the second gas to be introduced therein;
• a first piping extending from the second partition to reach below the third partition and being communicated with the first flow path,
• a second piping provided to enclose the first piping, extending from the third partition to reach below the third partition, and being communicated with the second flow path, and
• a convex portion provided on an outer circumferential surface of the first piping or an inner circumferential surface of the second piping and protruding from one of the outer circumferential surface of the first piping and the inner circumferential surface of the second piping toward the other one,
• wherein a bottom end of the convex portion is provided in a position separated upward from bottom ends of the first piping and the second piping.