The double-probe piezodriving specimen holder that was recently developed by some of the present authors is modified to introduce a laser irradiation port in one of its two arms. As a result, the new specimen holder consists of a piezodriving probe and a laser irradiation port, both of which can be three-dimensionally controlled by using piezoelectric elements and micrometers. While the piezodriving probe interacts with the specimen set in the holder in several ways, the laser beam causes photo-induced phenomena to occur. By performing electron holography using the new specimen holder, we demonstrate that it is possible to evaluate the change in the electric field resulting from the discharging effect of laser irradiation on organic photoconductors.