A method of manufacturing a semiconductor device includes performing a cycle a predetermined number of times, the cycle including supplying a first precursor containing a specific element and a halogen group to form a first layer and supplying a second precursor containing the specific element and an amino group to modify the first layer into a second layer. A temperature of the substrate is set such that a ligand containing the amino group is separated from the specific element in the second precursor, the separated ligand reacts with the halogen group in the first layer to remove the halogen group from the first layer, the separated ligand is prevented from being bonded to the specific element in the first layer, and the specific element from which the ligand is separated in the second precursor is bonded to the specific element in the first layer.