PURPOSE: To efficiently produce a plurality of surface conductive electron emitting elements arranged in a matrix in the way the elements have uniform properties.

CONSTITUTION: Surface conductive electron emitting elements arranged in a 6×6 matrix are divided into 2×2 small matrices 1-9. Forming for each element is carried out by applying pulses for every 10ms and then raising 0.1V and repeating these processes until the pulse voltage reaches 10V. While pulses being applied to one matrix 1, 1ms pulses can be applied to other eight small matrices successively at a moment of 10ms which is an interval between pulses. That is, forming for elements 1-9 can be carried out in parallel. In the case a unit to which pulses are applied simultaneously is as compact as 2×2, uniform forming can be carried out for each element.