PROBLEM TO BE SOLVED: To bring forward the formation of a cormel in a cultivation method of saffron.SOLUTION: A cultivation method of saffron includes: an anthesis induction step S102 to bloom the saffron grown up from a corm by maintaining a cultivation environment to a first air temperature in hydroponics and a cormel formation step S103 to make the corm form a cormel by maintaining the cultivation environment to a second air temperature that is lower than the first air temperature in hydroponics for at least ten days, after the anthesis induction step S102.