PROBLEM TO BE SOLVED: To provide a molten Al-Zn-based plated sheet steel produced without lowering continuous operability by suppressing dross generation, and having excellent corrosion resistance after paint application.SOLUTION: A molten Al-Zn-based plated sheet steel contains, in terms of mass%, Al:25-90% and Sn:0.01-10%, further 0.01-10% the total of one or more kinds selected from Mg, Ca and Sr, and furthermore possibly Zn:10-75%.