Disclosed is an apparatus for automatically measuring the amount of ink discharged from an inkjet printhead. A predetermined amount of pure water is injected into a measurement bottle, the bottle is supplied via an insertion port to a rotary table for measurement purposes, and the rotary table is rotated by 90.degree. to bring the bottle to a point immediately underlying a nozzle of the inkjet printhead. Ink is then discharged into the bottle from the printhead under set measurement conditions. The rotary head is then rotated a further 90.degree. to bring the bottle to a point in front of a photometer. At this time the ink solution is stirred thoroughly and the absorbance thereof is measured by the photometer. When measurement is completed, the rotary table is rotated a further 90.degree. to discard the bottle from a discharge port. These steps are automated by computer control.