Abstract: An inspecting device inspects the printed state of cream solder by projecting a plurality of light patterns varying in phase onto a printed circuit board printed with cream solder, and processing signals obtained by an image pick-up device for picking up the image on the surface of the printed circuit board using a phase shifting method. A printed position, area, thickness or amount of the cream solder can be detected. By comparing the data thus obtained with reference data, the printed state is evaluated. The printed state of the cream solder may be examined quickly and positively, while a continuous automatic processing can be effected without stopping the mounting process of the printed circuit board in a production line.