It is an object of the present invention to provide a mapping-data analyzing method that can display a map in which sufficient information is extracted from the spectra of obtained mapping data to enable objective analysis. The plurality of fuel injection holes include axially oriented injection holes and radially oriented injection holes such that fuel input through the plurality of fuel injection holes is injected in both a radial direction and an axial direction to mix with air flowing through the air slots. The second number can be less than, greater than, or equal to the first number.