Provided is a combustor comprising an entrance through which the fuel flows thereinto; a combustion chamber, connected to the entrance, having a larger cross-section area than that of the entrance; and a plurality of protrusions installed along the interface of the entrance and the combustion chamber. Thus, the combustor according to the present invention has an enhanced mixing capability of fuel and air in the combustion chamber, thereby having enhanced combustion efficiency and reduced discharge of harmful exhaust gas.