The utility model discloses a woodworking hole enlarger with an adjustable aperture and belongs to the field of hole enlargers. The hole enlarger comprises a circle centre positioning component, a first hole enlarging blade clamp and a hole enlarging arm, wherein the circle centre positioning component is fixed at a middle position of the hole enlarging arm; the first hole enlarging blade clamp is movably sleeved at a first end of the hole enlarging arm; a lower part of the circle centre positioning part is a positioning circular cone which is placed on a small positioning hole with the aperture of Phi 1-3mm; and a size scale layer is formed on a surface of the positioning circular cone. According to the woodworking hole enlarger, the aperture and the depth of the enlarged hole can be optionally and accurately adjusted in the range of certain aperture and depth of the enlarged hole, and an annular enlarged hole can also be accurately machined.