PURPOSE: To obtain an absorbing soln. compsn. inhibiting the corrosion, especially pitting corrosion of iron and iron alloys by adding polyethyleneimine to an aq. soln. contg. lithium bromide as the principal component.

CONSTITUTION: Polyethyleneimine is added to an aq. lithium bromide soln. having a high concn. of about 50-70% alkalified with lithium hydroxide, etc., and 0.1-1g/1 molybdate is further added if necessary. The amt. of the polyethyleneimine added is preferably 0.1-30g/l and the average mol. wt. is preferably 300-70,000. When the resulting aq. soln. is used as the objective absorbing soln. compsn., the corrosion, especially pitting corrosion of iron and iron alloys as the structural materials of an absorption refrigerator is remarkably inhibited and stable operation is enabled over a long period of time.