The comparisons between the electronic computer data and the experimental results of the characteristics of a three‐anode accelerating lens system for field emission scanning electron microscopy (FESEM) are described. Experimentally two characteristics were obtained. One of them is the relation between the accelerating voltages and the control voltages for the fixed working distance. The other is the variation of the current with the accelerating voltages. In comparison with the results of the electronic computer simulation, a close coincidence was found for the former case, but for the latter the experimental results are approximately half as large as those obtained theoretically.