Provided is a novel curable composition which is a two-pack type curable composition using an epoxy resin and an organic polymer having a crosslinkable silicon group, and which is free from curing delay or free from viscosity increase of the base material and deterioration of the base material such as gelation or precipitation of insoluble material, thereby exhibiting excellent storage stability. Also provided is a novel curable composition which exhibits excellent storage stability even if water is added thereto for the purpose of improving curability in a deep portion. A two-pack type epoxy resin composition according to the present invention is configured such that: the base material contains (A) an epoxy resin, (B) a compound having an Si-F bond and (C) an alkoxysilane that does not have at least one group selected from the group consisting of a primary amino group, a secondary amino group and a mercapto group; and a curing agent contains (D) an organic polymer having a crosslinkable silicon group and (E)
