A fuel injector includes: a pilot injector configured to spray fuel so as to form a first combustion region in a combustion chamber; and a main injector provided coaxially with the pilot injector so as to surround the pilot injector and configured to supply a fuel-air mixture that is a mixture of the fuel and air to form a second combustion region in the combustion chamber, wherein the main injector includes: a first inflow channel through which the air having a major flow component in an axial direction is taken; a second inflow channel through which the air having a major flow component in a radial direction is taken and which causes the air therein to meet the air from the first inflow channel; and a main fuel injecting portion configured to inject the fuel only to the second inflow channel.