A manually fed working machine including a working tool, a feeding area in front of the tool, a detector covering at least a section of the feeding area for a contactless detection of human skin, the detector comprising at least one radiation unit and at least one receiver unit. The at least one radiation unit emitting radiation towards said section of the feeding area, said radiation being emitted with at least two different wavelengths in the wavelength range between 900 nm and 1500 nm, whereas the at least one receiver unit receives the radiation reflected from the section of the feeding area, and a signal evaluation unit connected with the detector calculating the quotients or differences of the intensities of the reflected radiations received by the receiver unit and the at least two different wavelengths emitted from the radiation unit.