A gas fryer comprising: a tank for holding cooking oil, a heat pipe located proximate in the middle depth of said tank so that said heat pipe is soaked in said cooking oil, a combustion chamber located at the combustion gas inlet side of said heat pipe, and a flue located at a combustion gas outlet side of said heat pipe, wherein said heat pipe comprises a sleeve fitted in the inner wall of said heat pipe, and a spirally shaped mixer installed in said heat pipe, and wherein said flue comprises an introduction system of fresh air, said system comprising of a blowing nozzle of the fresh air positioned proximate to a narrowed region located proximate in the middle of said flue along a longitudinal axis, an inlet of fresh air located at a part of said flue, and a passage of fresh air provided along the inner and/or outer wall of said flue was provided.