An optical scanner, also known as a flux mapping system, capable of acquiring a flux distribution pattern of a light source on a 2-D flat surface, has been designed and constructed. The novel optical scanner can measure the light flux distribution at high resolution with fewer sensors in a relatively short amount of time, and it can be used for precise calibration of any light source. The design of the optical scanner consisted of a single row of photodiodes with fixed distances that can scan and acquire flux distribution data in the 2-D measurement plane. In our prototype design of the novel optical scanner, 25 photodiodes with a photosensitive area of 1 cm2 each were arranged in a single row and fixed to an aluminum holder. The resulting scanner was fast enough to perform scanning and recording of light irradiance over a test plane area of 1125 cm2 within a period of 5 s.