The automatic analyzer uses a marker that is to be attached to a measurement object. The marker is made of a substance that becomes excited when irradiated. The automatic analyzer has a function of varying irradiation intensity, and controls the intensity of light emitted from an item marker by adjusting the irradiation intensity for each analysis item or for each analysis vessel. Further, the automatic analyzer has a function of controlling the at least one of the position and angle of an analysis vessel during irradiation, and controls the amount of radiation to the measurement object by adjusting at least one of the distance and angle between an irradiation light source and analysis vessel for each analysis item. Furthermore, the automatic analyzer has a function of varying the integration time of photometric means and controls the integration time for each analysis item or for each analysis vessel.