The utility model relates to an anti-tilt ladder. The anti-tilt ladder comprises a flat ladder. According to the key point, support legs connected through rotating shafts are respectively arranged on two sides of the lower parts of two legs of the flat ladder; pin shafts connected with one ends of positioning rods are arranged on the support legs; chutes are formed in the positioning rods; positioning pins penetrating through the chutes of the positioning rods are respectively arranged at the lower ends of the two legs of the flat ladder and are connected with the other ends of the positioning rods through nuts in a sliding manner. The anti-tilt ladder is simple in structure and is convenient to use; the two support legs are additionally arranged based on an original flat ladder, so that the anti-tilt ladder can be supported on the ground by four legs, and the adhesive force is relatively strong; the intervals between the adjacent support legs can be adjusted, so that the use is relatively safe and reliable, and the technical problems in the prior art that the ladder is easy to tilt and has high risk factors are solved.