▎ 摘　　要

NOVELTY - Coating composition comprises calcium-based flame retardant, carbon-based flame retardant, adhesive and solvent. USE - The composition is useful for improving waterproof performance. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) foamed polystyrene with excellent flame retardancy and water repellency, comprising a foam. The flame retardant coating composition layer, formed on the foaming body. The flame retardant coating composition layer comprises the coating composition; and (2) manufacturing method of flame-retardant coating composition, comprising manufacturing first mixture comprising calcium-based flame retardant and carbon-based flame retardant, manufacturing second mixture comprising adhesive and solvent and manufacturing third mixture comprising first mixture and second mixture.