An acid decomposable compound of the present invention is a compound having acid decomposable groups and thermally-bond-formable groups in one molecule in a certain order. The acid decomposable compound contains at least a core structure, acid decomposable groups which are binding to the core structure and thermally-bond-formable groups which are binding to the acid decomposable groups, wherein the thermally-bond-formable groups undergo Diels-Alder Reactions, metathesis reactions or other thermal-addition reactions.