To provide a thermal spraying method capable of forming a thermal spray coating having a strong adhesion to the inner surface of a tubular substrate and uniform thickness.

This thermal spraying method comprises setting the tubular substrate 45 so as not to be rotated; setting a thermal spraying device 50 in the tubular substrate 45, which has a material feeding part 10 for feeding a thermal spraying material, and a melting/carrying part 25 for melting the thermal spraying material into spraying particles through radially jetting plasma flame and for carrying them in a radiation direction; and forming a spray coating 47 on the inner surface 46 of the tubular substrate 45, by moving the thermal spraying device 50 which is kept not to rotate, along an axis, in the tubular substrate 45.