PROBLEM TO BE SOLVED: To provide a pH-responsive liposome holding an objective substance under an acidic pH environment and releasing the objective substance under a basic pH environment.SOLUTION: The pH-responsive liposome is provided by containing a cationic amphiphatic molecule and at least one of an anionic amphiphatic molecule and ampholytic amphiphatic molecule as constituting lipids, and on dispersing it in an aqueous medium, having a positive zeta potential under an acidic environment of