PURPOSE: To permit a cutting tool to follow a marking line by projecting a collected light beam while sectioning its length onto a workpiece in front of the cutting tool, and guiding a hand-held tool so that the light beam coincides with the marking line.

CONSTITUTION: A lighting system 7 is installed in front of the casing 1 of a hand-held tool and causes a light beam 9 collected and widened into a delta- shaped light curtain 8 to be projected on a workpiece 5 located in front of the hand-held tool. The impinging light beam 9 is imaged as a line 10 extending in a cutting direction on the workpiece 5, in which case the sharply bounded line 10 can be viewed in a constant length. By guiding the hand-held tool so that the light beam 9 overlaps a marking line 11 throughout its length, a linear cut part can be obtained; that is, since the deviation from a target line can be immediately checked from an angle generated between the marking line and the line 10, the hand-held tool can be guided easily with high accuracy.