To reduce a working amount of a user by automatically collecting and preserving process data and also automatically calculating a data analysis value, etc.

This analyzer is provided with a trigger generating part 21 which generates a trigger signal when the value of process data that is always sampled is compared with, e.g. an upper bound value and a lower bound value of process data and when the value of the process data comes out of the range of the upper and lower bound values, generates a trigger signal from the part 21 when the value of process data which is undergone graph display in real time comes out of the range of the upper and lower bound values and starts to collect and to preserve data.