NOVELTY - Manufacture of mirror involves applying coating material (M1) containing polyvalent isocyanate compound in which isocyanate group is formed into blocks using active methylene-type blocking agent and polyvalent isocyanate compound in which isocyanate group is formed into blocks using from oxime-type blocking agent as curing agents (a1) and (a2), respectively, resin component and solvent to reflection layer side of glass substrate (12) having reflection layer (14) in one side, heating, and curing, to form cured coating film on reflection layer side of glass substrate.    USE - Manufacture of mirror used for solar heat-collecting system.    ADVANTAGE - The mirror having favorable quality is manufactured, with high productivity, and can be used in hostile environment such as desert area. The coating material used during manufacture of mirror has favorable hardenability and curtain flow property.    DETAILED DESCRIPTION - Manufacture of mirror involves applying coating material (M1) containing curing agents (a1) and (a2), resin component which is cured with the curing agents (a1) and (a2), and solvent to reflection layer side of glass substrate having reflection layer in one side by curtain flow-coating method, heating, and curing, to form a cured coating film on reflection layer side of glass substrate. The curing agent (a1) is a polyvalent isocyanate compound in which isocyanate group is formed into blocks using blocking agent(s) chosen from active methylene-type blocking agent, amine blocking agent, imine-type blocking agent and pyrazole-type blocking agent. The curing agent (a2) is a polyvalent isocyanate compound in which isocyanate group is formed into blocks using blocking agent(s) chosen from oxime-type blocking agent, triazole-type blocking agent, imidazole-type blocking agent, acid amide-type blocking agent and acid-imide-type blocking agent. The molar ratio of block-forming isocyanate group in curing agent (a1) and block-forming isocyanate group in curing agent (a2) is 5/95-30/70.    DESCRIPTION OF DRAWING(S) - The drawing shows a sectional view of the mirror.    Glass substrate (12)    Reflection layer (14)    Application layers (16A,18A)