To provide liquid fuel combustor intending to save energy by limiting the amount of energy thrown into the combustor from the outside to a necessary minimum.

In this liquid fuel combustor, an air supply port can be mounted to the location where air is directly supplied into a heat resistant alumina porous body having an optional and optimal hole diameter by classifying the size of the average hole diameter of the heat resistant alumina porous bodies into two kinds for each of upper and lower parts. In addition, it is structured so that reduction of the pressure loss of supplied air, self-continuation of reliable firing and liquid fuel vaporizing combustion requiring no auxiliary heat source, and stable combustion capable of sufficiently reducing discharge of carbon monoxide can be provided at the same time, by mounting an ultrasonic oscillation element on the center axis of the lowest part of a combustion vessel.