Si wafers were electrochemically grooved in HF solution using metal wires (Pt and Au wires) as catalytic wire electrodes and a Pt plate as a counter electrode. By applying anodic potentials of about 2.0 V vs Ag/AgCl to the Pt or Au wire electrodes, which were in contact with Si, Si was etched at the place where the wires were in contact. As a result, grooves were formed in Si. The widths of the grooves formed using Pt wires with diameters of 30 and 50 mu m were about 35 and 55 mu m, respectively. The grooving rate was typically in the range of 400-600 mu m/h at room temperature. The grooving rate was faster for the thinner wire electrodes because the diffusion of chemical species to and from the Si/Pt interface became easier for the thinner electrodes. The grooving rate was increased by increasing the anodic potential or temperature, although the Si surface was roughened to some extent under such conditions.