A workbench and an assistance method for manufacturing or checking electrical wiring harnesses. The workbench comprises: an assembly board; image projection devices on the assembly board; optical sensors arranged on the assembly board to provide information about its position; cameras arranged to capture gestures of the technician in charge of the workbench; a computer with a set of computer programs adapted to provide, through the image projection devices images in 1:1 scale of templates of the electrical wiring harness being manufactured or checked projected onto the assembly board and, superimposed on them, complementary images of aid requested by the technician, acting on virtual menus and/or buttons projected onto the assembly board.