To prevent a working mistake by allowing a worker to recognize or measure by knife and non-knife tools whether an edge part of the knife tool and a firing port of the non-knife tool keeps a predetermined working angle such as horizontal, vertical, tilting, or orientation.

The edge part of the knife tool, the firing port of the non-knife tool, and a body other than grappling sections of the tools are provided with a level, an indicia, or a level with indicia. The predetermined working angle such as horizontal, vertical, tilting, or orientation of the edge or the firing port of the tools is recognized or measured to allow accurate work.