A cutter for trimming tiles comprises generally a flat rectangular base, a first trapezoidal seat pivoted to one end of the base, a second trapezoidal seat sliding about an arcuate rail perpendicular to the other end of the base, a pair rail rods extended parallel to the axis of the base and secured at their two ends into the first and second trapezoidal seats respectively so that the rail rods can laterally swing about the arcuate therewithin. A cutting tool slides about the rail rod thereon having a cylinder shaft attached with a handle and a blade rotatably secured to the center of the cutting tool. So that cutter of the present invention can trim a straight line, a beveled straight line, a curve or a circle in a tile.