Provided are an agent for imparting ceramide-like function, an agent for reinforcing skin barrier function, a moisturizing agent and a skin drug for external use. The agent for imparting ceramide-like function comprises as an effective ingredient a derivative of succinic acid diamide represented by the following formula (1): [wherein R 1 and R 2 each independently represents a hydroxyalkyl group of from 1 to 6 carbon atoms, R 3 represents a group: -CH 2 CH 2 CH 2 CH 2 -R 4 or a group: -CH 2 CH=CHCH 2 -R 4 (wherein R 4 represents an alkyl group of from 8 to 26 carbon atoms)].
