A thermal spraying apparatus that forms an arc spray coating on a surface of a cylinder bore, wherein the thermal spraying apparatus at least comprises rotation control means (4, 52), ascent/descent movement control means (4, 51), and a spray gun that is rotated by the rotation control means (4, 52), that is moved in ascending/descending manner by the ascent/descent movement control means (4, 51), and that has at one end thereof a first discharge opening facing a direction that is orthogonal to an ascent/descent movement direction of the spray gun and that further has a second discharge opening facing a direction that is orthogonal to the direction that the first discharge opening faces; in the spray gun, a third discharge opening for discharging a fluid and that faces the same direction as the first discharge opening is provided at a predetermined region that is located further to the side in the ascent/descent movement direction of the spray gun than the first discharge opening; atomizing air is discharged from the first discharge opening and auxiliary air is discharged from the second discharge opening; and when the first discharge opening moves in ascending/ descending manner within the cylinder bore in the direction of the axial center thereof by means of the ascent/descent movement control means (4, 51) while the spray gun is in a rotating posture by means of the rotation control means (4, 52), the fluid is blown towards the bore surface in synchrony with the spraying of spray particles to the cylinder bore surface, said spray particles forming an arc spray coating on the bore surface; characterized in that the third discharge opening is arranged such that the discharged fluid is blown to a region that is separated in the upper direction by a distance from a deposition center of the arc spray coating sprayed and deposited on the bore surface, thereby setting an appropriate separation for this L, preventing spray fumes from adhering to regions which are above the currently sprayed region and its vicinity, and on which a spray coating is to be later formed. the thermal spraying apparatus at least comprises rotation control means (4, 52), ascent/descent movement control means (4, 51), and a spray gun that is rotated by the rotation control means (4, 52), that is moved in ascending/descending manner by the ascent/descent movement control means (4, 51), and that has at one end thereof a first discharge opening facing a direction that is orthogonal to an ascent/descent movement direction of the spray gun and that further has a second discharge opening facing a direction that is orthogonal to the direction that the first discharge opening faces; in the spray gun, a third discharge opening for discharging a fluid and that faces the same direction as the first discharge opening is provided at a predetermined region that is located further to the side in the ascent/descent movement direction of the spray gun than the first discharge opening; atomizing air is discharged from the first discharge opening and auxiliary air is discharged from the second discharge opening; and when the first discharge opening moves in ascending/ descending manner within the cylinder bore in the direction of the axial center thereof by means of the ascent/descent movement control means (4, 51) while the spray gun is in a rotating posture by means of the rotation control means (4, 52), the fluid is blown towards the bore surface in synchrony with the spraying of spray particles to the cylinder bore surface, said spray particles forming an arc spray coating on the bore surface; characterized in that the third discharge opening is arranged such that the discharged fluid is blown to a region that is separated in the upper direction by a distance from a deposition center of the arc spray coating sprayed and deposited on the bore surface, thereby setting an appropriate separation for this L, preventing spray fumes from adhering to regions which are above the currently sprayed region and its vicinity, and on which a spray coating is to be later formed.