Ink jet technology has advantages such as high-resolution and a multicolor printing capability and has a good potential for computer-based three-dimensional (3D) fabrication. The authors have developed an ink jet 3D bioprinter to manufacture biologically viable 3D structures using living cells. They have developed an effective method for the fabrication of 3D hydrogel structures by using ink jet technology with a liquid aqueous gelating medium, which is essential in fabricating 3D structures with living cells. In the present study, they evaluated the feasibility of the ink jet approach for digital 3D biofabrication, analyzing the microgel beads produced by the ink jet droplets. The ink jet droplets of sodium alginate solution, which were ejected into CaCl₂ solution, gelled to form microgel beads. The resulting beads were analyzed by means of image-based particle analysis to show that homogeneously sized microgel beads were effectively produced. Ink jet 3D biofabrication has a high potential for effective digital fabrication with such homogeneous microgel beads and will provide promising approaches for sophisticated computer assisted tissue engineering.