Fuente: WIPO "milk" Provided is a novel sleep-promoting composition.Provided is a sleep-promoting composition comprising bacteria belonging to Bifidobacterium breve as an active ingredient. The sleep-promoting composition related to the present technology may prolong a sleep time by prolonging non-REM sleep and REM sleep, reducing a spontaneous behavior amount during sleep, or reducing an awakening time during sleep. The sleep-promoting composition related to the present technology may also reduce difficulty in daytime awakening. The sleep-promoting composition related to the present technology may be used for a medical composition or a food and beverage composition.