To provide an adhesive agent composition for roofing tiles, which can be used for binding a roofing tile to a waterproof sheet and which has improved creeping resistance and long adhesivity at high temperature.

The adhesive agent composition is used for fixing roofing tiles and is a butyl rubber based adhesive agent composition for roofing tiles including: (1) 100 parts by mass of a butyl rubber; (2) 0.2-5 parts by mass of a silane coupling agent; and (3) 2-35 parts by mass of polyethylene. By making a butyl rubber based adhesive agent contain the silane coupling agent and polyethylene , the adhesive agent composition having drastically improved creep resistance and long term adhesivity at high temperatures is provided.