This paper describes a system which enables fast 3-dimensional measurement of a human head by means of a slit-ray projection method. The system developed here consists of a laser slit-ray projector, two CCD TV cameras, a real-time video signal processor and a 16-bit computer. Due to the employment of this real-time video signal processor and a fast data-processing technique for using a look-up table, a 3-dimensional measurement of the human head can be accomplished in 4.3 seconds, and all the image data are converted to 3-dimensional data in 1 second. Experimental data reveal the applicability of our system.