A tattooing apparatus, which have a tattoo needle traveling back and forth to a skin to allow a staining solution for tattoo contained in the apparatus to penetrate into the skin and thus to get a tattoo and which can adjust a concentration of the staining solution for tattoo, is disclosed. The tattooing apparatus includes a chamber pressure adjusting member to adjust a degree of opening and closing an inlet of a storing chamber in which the staining solution for tattoo is stored, thus to adjust a pressure in the storing chamber.