An evaporator and a fuel reformer having the same. The evaporator includes a wall arrangement having a circumferential wall and a bottom wall, the circumferential wall and the bottom wall defining (or surrounding) an evaporation chamber; an inlet provided at one side of the evaporation chamber; an outlet formed in the bottom wall; and a barrier at (or surrounding) the outlet and projected from the bottom wall to the inside of the evaporation chamber.