A thermally sprayed coating (12) is formed by: preheating a cylinder block (1); and then inserting a thermal spray gun (2) successively into cylinder bores (6A to 6D) and spraying molten metal droplets (11) onto the inner surface of each cylinder bore while exhausting air from at least the lower surface of the cylinder block (1). Thermal spraying is performed by leaving an interval of at least one cylinder between the cylinder bore that was thermally sprayed first and the cylinder bore to be thermally sprayed next.
