A primer composition comprising: (A) 100 parts by weight of a reactive acrylic resin comprising a main chain composed of a copolymer of two types of alkylmethacrylates having different number of carbon atoms and a side chain having a group with a hydroxyl group and at least one aromatic ring; (B) 100 to 500 parts by weight of a silane compound obtained by reaction of an aminosilane having two amino groups with dialkoxyepoxysilane and trialkoxyepoxysilane at a predetermined ratio; (C) 10 to 300 parts by weight of an epoxy resin of bisphenol A type having an epoxy equivalent of 1,000 to 2,000 g/eq.; and (D) 100 to 500 parts by weigh of carbon black is provided. The composition is excellent in storage stability and can retain excellent adhesion during the time from the coating of the primer until the coating of a sealant and further is excellent in weatherability.