In a perimeter 2 having means 19 for setting a measurement coordinate system CS for perimetry, a means 13 for detecting a position M1 of a blind spot of a subject eye based upon the set measurement coordinate system CS, a means 19 for measuring a visual field of the same subject eye 22a on the basis of the respectively set measurement coordinate systems CS F and CS N at the first point of time and a subsequent second point of time after the first point of time, such a perimeter has a means 11 for storing the position (r, ¸ ) of the blind spot that is detected at the first point of time in a memory 15, a means 16 for detecting the position (r', ¸ ') of the blind spot of the subject eye at the perimetry in the second point of time of perimetry and computing amount of deviation (±) with the position (r, ¸ ) of the blind spot at the first point of time, and a means 17 for conducting such an operation that the new measurement coordinate system CS N is moved on the basis of the amount of deviation (±) so as to correspond with the measurement coordinate system CS F at the first point of time, and conducts the perimetry on the basis of the measurement coordinate system CS N that correspond with the measurement coordinate system CS F at the first point of time.
