PURPOSE: To detect the position shift of a mounted component at the time of the inspection of a mounted printed board without being affected by circumfer ential environment in the inspection as to the component position shift detecting method by the mount appearance inspection device which inspects the position shift of the electronic component on the printed board used for electronic or electric equipment.

CONSTITUTION: As for the component position shift detecting method by the mount appearance inspection device which detects the position shift of the mounted component on the printed board by obtaining image data by scanning the mounted printed board by a camera, a position shift arithmetic part 51 which inputs image data on both end edge parts of the mounted component at least in one direction between image data 34 and 35 obtained from the mounted printed board to be inspected as window data 48 and 49 in two specific ranges and calculates the difference between the counted values of 0's or 1's of binary-coded data of the two window data 48 and 49 is provided to detect whether or not the mounted component shifts.