Abstract: An electric marking device for tattooing humans, animals, and for other applications comprises a frame assembly having a rectangular prismatic base and a pair of side plates secured to opposite sides of the base, an electromagnet assembly mounted on the base between the side plates, an armature assembly adjustably mounted between the side plates above the electromagnet assembly, an interrupter switch supported between the side plates above the armature assembly, a needle guide assembly holder pivotally supported to the front of the base, a locator key slot provided in the needle guide assembly holder, a tubular needle guide assembly including a central tubular handpiece and upper and lower tubular extensions, a positioning collar secured on the upper extension in predetermined position, a locator key secured to the positioning collar, the needle guide assembly being removably assembled with the needle guide assembly holder in predetermined position by mating the locator key of the positioning collar with the