Cracks appearing on concrete or mortar of structures would reduce the life of structure and destroy its functions, because they cause permeation or penetration of air and moisture. For example, water permeation and air penetration through such cracks promote a corrosion of steel frames and bars.As a procedure to avoid such unfavorable consequences, cement paste or natrium silicate anhydride of inorganic material has been hitherto used to repair such cracks. Those materials have fulfilled the purpose of repairing such cracks to some degree, but not to the fullest satisfaction.In recent years, thanks to rapid development in the use of high polymer materials, they have been introduced into the field of concrete engineerings, and found not only to be applicable to, but most useful for, repair works of concrete cracks.This paper is intended to refer to the studies made on the use of Epoxy resin as a filler for concrete and mortar cracks instead as an adhesive agent widely being employed for concrete and mortar works.