Abstract: The present invention provides a thermally crosslinking type curable composition having the following excellent performance and properties: it needs no poly vinyl chloride resin, and exhibits excellent adhesiveness even to aluminum alloy materials and the like. The curable composition is characterized in that a diluent and an adhesion promoter are compounded with a composition containing uncrosslinked type and/or partially crosslinked type synthetic rubber, a plasticizer, a filler and a core-shell type acrylic resin. As the diluent, there are preferably used paraffinic or naphthenic hydrocarbons obtained by distillation of crude oil, or chemically synthesized hydrocarbons which are the second or third class petroleum having a molecular weight of 200 or less.