The present invention is a urethane-type polymer obtained by a reaction of:a monohydroxy compound (A) represented by Formula (1),R1C2H4—OmH (1)wherein R1 is an aliphatic hydrocarbon group having 24 to 36 carbon atoms, and m represents a number ranging from 0 to 1000a polyethylene glycol (B) represented by Formula (2),HOC2H4—OnH (2)wherein n represents a number ranging from 2 to 1000a monoglyceryl ether compound (C) represented by Formula (3),wherein R2 represents an aliphatic hydrocarbon group having 5 to 12 carbon atoms and an isocyanate compound (D) represented by Formula (4),R3NCO]q (4)wherein R3 represents a hydrocarbon group having 4 to 13 carbon atoms, and q represents the number 2 or 3.This urethane-type polymer can be used as a urethane-type viscosity modifier excellent in long-term storage stability, similarly to alkali thickening-type viscosity modifiers, while having characteristics similar to those of existing urethane-type viscosity modifiers.
