An apparatus for atomizing a sample comprises a cuvette of heating material into which a sample is introduced, a pair of electrodes of supplying an electric current to the cuvette, thereby heating and atomizing the sample, supports of supporting the pair of the electrodes, a means for supplying light to the atomized sample and a means of slidably maintaining at least one of the pair of the electrodes against the cuvette in a predetermined range of contact pressures, where the heating temperature of the cuvette can be maintained constant with improved reproducibility of analytical values.