PROBLEM TO BE SOLVED: To provide a method for preventing or ameliorating tissue depigmentation.SOLUTION: The method for preventing or ameliorating tissue depigmentation is established by finding that WNT1, WNT3A, WNT7A, WNT7B, WNT10B and NORRIN being substances for activating WNT signaling pathway exhibit remarkable preventing and ameliorating effect on tissue depigmentation by using a technique for screening a substance showing a preventing or ameliorating effect on tissue depigmentation more precisely, quickly and accurately.