Abstract: The invention relates to a skin contact detecting device (1) for a device (24) to be secured, comprising a contact piece (2) with a bearing surface (3) and comprising a safety circuit (7) with a light source (6), a photodetector (9), and an analyzing circuit (17). The bearing surface (3) has a light outlet portion (4) and a light inlet portion (5) which is delimited by the light outlet portion. Furthermore, the light source (6) has a main beam direction (8) of the emitted electromagnetic radiation, said main beam direction being oriented in the direction of the light outlet portion (4). The photodetector (9) has a detecting region (10) for electromagnetic radiation, said detecting region being oriented in the direction of the light inlet portion (5). The light source (6) is designed to emit light of a first (13) and at least one second (14) wavelength, and the photodetector (9) is sensitive to the first (13) and the second (14) wavelength.