the fundus of the eye or the two directions of light reception of the light receptor application_number US 35016394 A description a first embodiment of the present invention will hereinafter be described in detail with reference to fig2 to 4 referring to fig2 which shows the construction of an eye fundus blood flow meter according to the present embodiment a band pass filter 23 transmitting only yellow and green beams of light therethrough a condenser lens 24 a mirror 25 a field lens 26 a ring slit 27 relay lenses 28 29 an apertured mirror 30 and an image rotator 31 are disposed on an optical path leading from an illuminating light source 21 comprising a tungsten lamp or the like emitting white light to an objective lens 22 light detecting optical system 35 in which a pair of small mirrors 32a 32b a pair of lenses 33a 33b and a pair of photomultipliers 34a 34b are disposed on optical paths extending upwardly in two directions from the opening portion of the apertured mirror 30 in fig2 in order to avoid duplication only the members on the optical axis of the small mirror 32a of the pair of small mirrors 32a 32b are shown an image stabilizer 36 is disposed on an optical path behind the apertured mirror 30 and lenses 37 38 a galvanometric mirror 39 lenses 40 41 and a galvanometric mirror 42 are disposed in succession in the image stabilizer 36 the galvanometric mirrors 39 and 42 are rotatable by means of an operating rod 43 the galvanometric mirror 39 is rotated about a rotational axis perpendicular to the plane of the drawing sheet of fig2 and the galvanometric mirror 42 is rotated about a.