Abstract: The present invention is directed to a tool for cutting sandwich type plaster boards such as gypsum plaster boards. It is an object of the present invention to provide a tool which allows the exact cutting of those boards in a time saving manner. According to the present invention this object is performed by a tool for working board-like workpieces, in particular sandwich type plaster boards, comprising a guide means for guiding the tool, a handle means, a blade means for forming a cut in the workpiece, and a coupling means for coupling the blade means with the guide means in an adjustable manner. A spacing between the handle means and the blade means may be adjusted by said coupling means in a direction transversely to a moving direction of the blade means.