The invention discloses a sinking technology for expanding a pilot well drilled by a raise-boring machine, by using a vertical well heading machine, which comprises the following steps of (a) drilling the pilot well by using the raise-boring machine; (b) drilling by using the vertical well heading machine to enable the pilot well to be enlarged into a vertical well at a desirable diameter in a brushing way; (c) hanging a net on and jetting concrete onto the wall of the vertical well to form a temporary supporting well wall; (d) after enlarging in the brushing way and heading to a lower tunnel by using the vertical well heading machine, gradually removing components of the vertical well heading machine from top to bottom. By the adoption of the technology provided by the invention, in the presence of the pilot well, a vertical well hole at a design diameter is formed through the one-time drilling of the vertical well heading machine; therefore the technology is applicable for the construction of underground mine vertical well holes for coal mining, metal, nonmetal and the like.