To provide a high-strength steel sheet that has excellent chemical treatment properties and corrosion resistance after electrodeposition coating, and to provide a method of producing the same.

A steel sheet comprises, by mass, 0.01 to 0.18% C, 0.4 to 2.0% Si, 1.0 to 3.0% Mn, 0.001 to 1.0% Al, 0.005 to 0.060% P, ≤0.01% S, and a balance comprising Fe with inevitable impurities. When the steel sheet is continuously annealed, a heating step is conducted at a hydrogen concentration in an atmosphere of ≥22 vol% in a temperature region of a heating furnace temperature from ≥600°C to ≤A°C, and at a dew point in the atmosphere of ≥-8°C in a temperature region of the heating furnace temperature from >A°C to ≤B°C, provided that A and B respectively satisfy 680≤A≤780 and 800≤B≤900.