Provided is an optical sorter including a chute arranged in an inclined manner such that objects to be sorted flow down, an optical detecting unit configured to detect the objects to be sorted at a detection position, and an ejector unit configured to sort and remove the objects to be sorted based on a result of detection obtained by the optical detecting unit. The optical detecting unit includes an illuminating unit configured to illuminate the detection position, and an imaging unit configured to image the objects to be sorted at the detection position. The chute is provided with an optical detection slit orthogonally crossing a flowing down direction of the objects to be sorted. The optical detecting unit images the objects to be sorted flowing down on the chute with the imaging unit using a position at which the optical detection slit is provided as the detection position.