An automated analyzer comprising: a receptacle holding portion for holding a plurality of receptacles in which aliquots of liquid are stored; a probe cleaning device configured to provide immersion cleaning of the tip of a dispensing probe operative to collect the aliquots of liquid from the receptacles held to the receptacle holding portion, and provided with a probe cleaning bath arranged in a trajectory of movement of the dispensing probe; and an immersion cleaning solution holding portion for storing an immersion cleaning solution, wherein the probe cleaning bath has a cleaning solution supply tube arranged in the upper portion thereof and a waste liquid tube arranged in the lower portion thereof, and the immersion cleaning solution holding portion is provided within the probe cleaning bath and has an immersion cleaning solution supply tube arranged in the lower portion thereof; the automated analyzer further comprising: an aliquot dispenser equipped with a drive mechanism for holding the dispensing probe such that the dispensing probe can be moved between the receptacle holding portion and the immersion cleaning solution holding portion; a measurement controller for controlling the drive mechanism of the aliquot dispenser and the dispensing probe such that the aliquots of liquid are successively collected at given cycles from the receptacles held to the receptacle holding portion; and an immersion cleaning controller for controlling the drive mechanism of the aliquot dispenser and the dispensing probe such that an immersion cleaning operation in which the dispensing probe is immersed in the immersion cleaning solution stored in the immersion cleaning solution holding portion is carried out for an immersion time that is at least twice as long as the period of each of the given cycles and then a cleaning operation in which the dispensing probe is moved into the probe cleaning bath such that the dispensing probe is cleaned with the cleaning solution supplied from the cleaning solution supply tube is carried out. a receptacle holding portion for holding a plurality of receptacles in which aliquots of liquid are stored; a probe cleaning device configured to provide immersion cleaning of the tip of a dispensing probe operative to collect the aliquots of liquid from the receptacles held to the receptacle holding portion, and provided with a probe cleaning bath arranged in a trajectory of movement of the dispensing probe; and an immersion cleaning solution holding portion for storing an immersion cleaning solution, wherein the probe cleaning bath has a cleaning solution supply tube arranged in the upper portion thereof and a waste liquid tube arranged in the lower portion thereof, and the immersion cleaning solution holding portion is provided within the probe cleaning bath and has an immersion cleaning solution supply tube arranged in the lower portion thereof; the automated analyzer further comprising: an aliquot dispenser equipped with a drive mechanism for holding the dispensing probe such that the dispensing probe can be moved between the receptacle holding portion and the immersion cleaning solution holding portion; a measurement controller for controlling the drive mechanism of the aliquot dispenser and the dispensing probe such that the aliquots of liquid are successively collected at given cycles from the receptacles held to the receptacle holding portion; and an immersion cleaning controller for controlling the drive mechanism of the aliquot dispenser and the dispensing probe such that an immersion cleaning operation in which the dispensing probe is immersed in the immersion cleaning solution stored in the immersion cleaning solution holding portion is carried out for an immersion time that is at least twice as long as the period of each of the given cycles and then a cleaning operation in which the dispensing probe is moved into the probe cleaning bath such that the dispensing probe is cleaned with the cleaning solution supplied from the cleaning solution supply tube is carried out. an aliquot dispenser equipped with a drive mechanism for holding the dispensing probe such that the dispensing probe can be moved between the receptacle holding portion and the immersion cleaning solution holding portion; a measurement controller for controlling the drive mechanism of the aliquot dispenser and the dispensing probe such that the aliquots of liquid are successively collected at given cycles from the receptacles held to the receptacle holding portion; and an immersion cleaning controller for controlling the drive mechanism of the aliquot dispenser and the dispensing probe such that an immersion cleaning operation in which the dispensing probe is immersed in the immersion cleaning solution stored in the immersion cleaning solution holding portion is carried out for an immersion time that is at least twice as long as the period of each of the given cycles and then a cleaning operation in which the dispensing probe is moved into the probe cleaning bath such that the dispensing probe is cleaned with the cleaning solution supplied from the cleaning solution supply tube is carried out.