Described herein is a technique capable of providing a semiconductor device having good characteristics. According to the technique described herein, there is provided a method of manufacturing a semiconductor device, including: (a) loading a substrate into a process chamber; and (b) forming a stacked etch stopper film by performing: (b-1) forming a first etch stopper film containing a first element and a second element by supplying a first element-containing gas and a second element-containing gas onto the substrate; and (b-2) forming a second etch stopper film containing the first element, the second element and a third element by supplying the first element-containing gas, the second element-containing gas and a third element-containing gas onto the first etch stopper film.