The present disclosure relates to a cement mortar additive and a method of manufacturing the same. More particularly, the present disclosure relates to a cement mortar additive for solving the inhomogeneity, which is a problem caused by the deliquescence of urea, so that the deterioration of the physical properties of a cement mortar is prevented and the open time, water retentivity, and workability of the cement mortar are improved, and to a method of manufacturing the cement mortar additive.