Abstract: A mark image processing device has an imaging control unit which captures images of an alignment mark on a work a plurality of times while changing an image capturing condition such as lighting intensity or exposure time by an imaging device and an image recognition unit which computes correlation between the plurality of images and a template image of the mark, which is registered in advance, and detects an optimal mark position.

Abstract: A movable member moves along a predetermined guide path. A supporting member extends from the movable member. A processing unit is fixed to the tip end of the supporting member. A sensor detects the movement of the movable member. When the movable member has stopped moving, the processing unit is subjected to a transient due to the inertia acting on the processing unit. The transient is detected based on the waveform of the sensor signal. The position of the processing unit can thus precisely be detected based on the sensor signal. The time for starting the operation of the processing unit can optimally be determined. The processing unit is thus allowed to start operating at the determined time. The processing unit is allowed to start operating in a shorter time after the movable member has stopped moving, even when the transient remains in the processing unit.