PROBLEM TO BE SOLVED: To provide a material capable of suppressing fat cell differentiation and maturation or fat accumulation and effective for prevention and amelioration of symptoms due to adiposity.SOLUTION: A fat cell differentiation and maturation and/or fat accumulation suppressor includes, as an effective ingredient, a C-terminus amidated polypeptide comprising an amino acid sequence wherein 0-3 amino acids are connected to the N-terminus side of an amino acid sequence represented by a sequence number 1.