A combustor of a gas turbine engine, comprising: a fuel injection unit including a fuel spray part configured to spray a fuel so that a diffusion combustion region is formed in a combustion chamber, and a pre-mixture supply part configured to supply a pre-mixture of a fuel and an air so that a pre-mixture combustion region is formed in the combustion chamber; and a fuel supply unit configured to supply the fuel to the fuel spray part and the pre-mixture supply part, wherein the fuel supply unit includes: a pilot fuel passage and a main fuel passage configured to supply the fuel to the fuel spray part and the pre-mixture supply part, respectively; an assembled fuel passage configured to supply the fuel to the pilot fuel passage and the main fuel passage; and a fuel distributor disposed at a branch point where the assembled fuel passage is connected to both of the pilot fuel passage and the main fuel passage, the fuel distributor being configured to automatically control amounts of the fuel to be distributed to the pilot fuel passage and to the main fuel passage in accordance with a pressure of the fuel, wherein the fuel distributor includes a fuel inlet into which the fuel is introduced from the assembled fuel passage, and a pilot port and a main port which are respectively connected to the pilot fuel passage and the main fuel passage, wherein the pilot port, the main port and the fuel inlet are formed on a housing, and a movable body comprising a piston is housed in the housing, characterized in that the pilot port includes a first port and a second port which have different passage areas from each other, wherein the passage area of the first port is set to be greater than that of the second port, wherein the movable body is configured to be moved in accordance with the pressure of the fuel at the fuel inlet so as to bring only the pilot port in communication with the fuel inlet upon a lower fuel pressure operation and bring both of the pilot port and the main port in communication with the fuel inlet upon a moderate fuel pressure operation as well as upon a higher fuel pressure operation, wherein the movable body is configured to move so as to bring only the first port in communication with the fuel inlet upon the lower fuel pressure operation, wherein the movable body is configured to move so as to bring the first port as well as the second port in communication with the fuel inlet upon the moderate fuel pressure operation, and wherein the movable body is configured to move so as to bring only the second port in communication with the fuel inlet upon the higher fuel pressure operation. a fuel injection unit including a fuel spray part configured to spray a fuel so that a diffusion combustion region is formed in a combustion chamber, and a pre-mixture supply part configured to supply a pre-mixture of a fuel and an air so that a pre-mixture combustion region is formed in the combustion chamber; and a fuel supply unit configured to supply the fuel to the fuel spray part and the pre-mixture supply part, a pilot fuel passage and a main fuel passage configured to supply the fuel to the fuel spray part and the pre-mixture supply part, respectively; an assembled fuel passage configured to supply the fuel to the pilot fuel passage and the main fuel passage; and a fuel distributor disposed at a branch point where the assembled fuel passage is connected to both of the pilot fuel passage and the main fuel passage, the fuel distributor being configured to automatically control amounts of the fuel to be distributed to the pilot fuel passage and to the main fuel passage in accordance with a pressure of the fuel, wherein the fuel distributor includes a fuel inlet into which the fuel is introduced from the assembled fuel passage, and a pilot port and a main port which are respectively connected to the pilot fuel passage and the main fuel passage, wherein the pilot port, the main port and the fuel inlet are formed on a housing, and a movable body comprising a piston is housed in the housing, characterized in that the pilot port includes a first port and a second port which have different passage areas from each other, wherein the passage area of the first port is set to be greater than that of the second port, wherein the movable body is configured to be moved in accordance with the pressure of the fuel at the fuel inlet so as to bring only the pilot port in communication with the fuel inlet upon a lower fuel pressure operation and bring both of the pilot port and the main port in communication with the fuel inlet upon a moderate fuel pressure operation as well as upon a higher fuel pressure operation, wherein the movable body is configured to move so as to bring only the first port in communication with the fuel inlet upon the lower fuel pressure operation, wherein the movable body is configured to move so as to bring the first port as well as the second port in communication with the fuel inlet upon the moderate fuel pressure operation, and wherein the movable body is configured to move so as to bring only the second port in communication with the fuel inlet upon the higher fuel pressure operation.