The present invention relates to epoxy resin coating composition which comprises, at least, epoxy resin, a thiol-type curing agent and a curing assistant, being composed of two liquids of liquid (A) containing epoxy resin and a thiol-type curing agent and liquid (B) containing a curing assistant, which liquids are mixed just before using, wherein the thiol-type curing agent contains a branched compound containing a thiol group (P), which compound is an ester of polyhydric alcohol with thiol group-containing carboxylic acid represented by formula (1) HOCO(CH2)nCR1R2SH  (1) (in the formula, R1 represents a hydrogen atom or a linear or branched alkyl group having 1 to 10 carbon atoms, R2 represents a linear or branched alkyl group having 1 to 10 carbon atoms, and n represents an integer of 1 to 4), which exhibits a suitable pot life, excellent curability particularly at low and ordinary temperature and low toxicity.