Abstract: A tertiary nitrogen atom-containing urethane polymer which comprises units of the following formulas (I) and (II) as the essential components and units of the following formulas (III), (IV) and (V) as the optional components, the content of the unit of the formula (I) being not less than 10 milliequivalents in terms of the tertiary nitrogen atom per kilogram of the urethane polymer, and has a molecular weight of not less than 500: ##STR1## wherein R.sub.1 and R.sub.2 are each a C.sub.1 -C.sub.4 alkyl group and, when taken together with the adjacent nitrogen atom to which they are attached, represent a nitrogen-containing heterocyclic group, R.sub.3 is a C.sub.1 -C.sub.4 alkyl group, R.sub.4 is an optionally branched C.sub.1 -C.sub.8 alkylene group, m is a positive integer and n is zero or a positive integer but m+n is a number which can provide the unit of the formula (I) with a molecular weight of 131 to 6998 and the bondings in the unit of the formula (I) may be in random and/or block, R.sub.