A structure for securing a faucet to a countertop

The invention relates to a fixing structure for a faucet 10 to secure the faucet on a sink countertop 2. The structure comprises a housing 11, a pull-out spray head 12, a mixing valve 13, and a water supply set 14. The water supply set includes a cold-water inlet pipe 141, a hot-water inlet pipe 142, and a mixing outlet pipe 143. The structure also comprises a positioning device 100 having a base 20 with a peripheral wall 21, a bottom wall 22, and an aperture 23. The bottom wall has a limiting face 24 and at least one orifice. The limiting face has a channel (242 figure 5), two stop posts (25 figure 4), and an abutting face (222 figure 4). Two screw rods (30 figure 4) extend out of the hole and are rotated above the base. Two clamping blocks (40 figure 4) are screwed onto the two screw rods, and are limited by the two stop posts. When the two screw rods are rotated, the two clamping blocks move upwardly to abut a bottom end of the sink countertop.