Disclosed is a surface-treated precoated 
metal sheet of which resistance against 
contamination with a photocatalyst and a self-cleaning function can be retained for a long period. Also disclosed are a method and a surface-treating solution for producing the surface-treated precoated 
metal sheet properly. The surface-treated precoated 
metal sheet is characterized by comprising a precoated 
metal sheet comprising an under 
metal sheet and an organic 
resin coating layer provided on the surface of the under 
metal sheet and a 
coating film having at least two 
layers, having a photocatalytic activity and formed on the precoated metal sheet, wherein the 
coating film having at least two 
layers comprises an inorganic-organic composite resin composed of a condensed product of an alkoxysilane selected from a group consisting of an alkoxysilane having an 
organic group selected from a group consisting of an 
alkyl group having 1 to 12 carbon atoms, an 
aryl group, a carboxyl group, a 
hydroxy group and a combination of two or more of these groups, an alkoxysilane having an 
epoxy group, an alkoxysilane having an amino group, a tetraalkoxysilane and a combination of two or more of the alkoxysilanes and contains a substance having a photocatalytic activity in such an amount that the content of the substance is highest in the outermost layer of the 
coating film and is gradually decreased toward an inner layer of the coating film.