A method of manufacturing a semiconductor device includes: preparing a substrate processing apparatus including a substrate process chamber having a plasma-generation space where a nitrogen-containing gas is plasma-exited and a process space where a substrate is mounted in communication with the plasma-generation space, an inductive coupling structure configured by a coil and an impedance matching circuit, wherein electric field combining the coil and the circuit has a length of an integer multiple of a wavelength of an high-frequency power, and a table to mount the substrate under a lower end of the coil; mounting the substrate on the table; supplying the nitrogen-containing gas into the chamber; starting a plasma excitation of the nitrogen-containing gas by applying the high-frequency power to the coil; and nitriding a surface of the substrate with active species containing a nitrogen element at an internal pressure of the chamber ranging from 1 to 100 Pa.