This coated steel sheet comprises: a steel sheet; a primer coating film that is arranged on the steel sheet and contains a chromic acid-based rust preventive pigment and aggregate that serves as primary particles, while not containing porous particles; and a top coating film that is arranged on the primer coating film. The aggregate satisfies the following formula (1) and formula (2). D 10 ‰¥ 0.6 T D 90 < 2.0 T (In the formulae, D 10 represents the 10% particle diameter (µm) of the aggregate in the number-based cumulative particle size distribution; D 90 represents the 90% particle diameter (µm) of the aggregate in the number-based cumulative particle size distribution; and T represents the film thickness (µm) of a portion of the primer coating film, in which the aggregate is not present.)