A perimeter having means for setting a measurement coordinate system CS, a detector for blind spots, a means for measuring a visual field of the same subject eye based on set measurement coordinate systems at a first and second point of time and a memory for storing the position of the blind spot, a detector for detecting the position of the blind spot at the second point of time and computing amount of deviation with the position of the blind spot, and a control for conducting new measurement coordinate based on the deviation (α).
