Abstract: The invention concerns a device for non-invasive detection of malignant processes in human body. Diagnostically informative optical data are obtained by exposing human fingertips to pulsed electric fields strong enough to initiate atmospheric pressure corona discharge. The device that provides reliable information useful for detection of cancer-specific spectral signatures comprises a transparent electrode (4) to generate electric impulses, which is covered by a rigid transparent insulator (3); a flexible transparent membrane (2) positioned loosely on the free surface of the rigid insulator to facilitate the recombination processes; a dark opaque membrane (1) positioned on the transparent membrane to eliminate spurious light; an image-receiving camera (5) mounted beneath the optically transparent electrode and a computer to operate the device and process recorded data.