To obtain an injecting method and injecting mechanism for fuel injection burner by which the air pollution can be suppressed by remarkably reducing the occurrence of NOx from the conventional boiler.

A fuel injection burner is constituted of an sprayer 1, a back plate, and three pieces of parts. A central groove-shaped hole 5 is provided on the inside of the atomizer 1 and an outer peripheral groove 6 is provided on the outside of the atomizer 1. A plurality of injection holes 7 which are communicated with the outside of the atomizer 1 is provided between the central groove-shaped hole 5 and outer peripheral groove 6 and flowing-in grooves 8 are provided in the directions of the tangents to the injection holes 7 from the groove-shaped hole 5 and outer peripheral groove 6 so that fuel can be sprayed in a whirling state. The whirling direction of the fuel is faced oppositely to the whirling direction 12 of air for combustion and, at the same time, the injection holes 7 are also faced to each other by inclining the holes 7 at angles 13.