To perform sterilization using a sterilization member that has a treatment surface that is a surface on which a plurality of protrusions each having a leading end that is thinner than a diameter of a microorganism that is to be killed are provided, a sterilization member on which each protrusion has a height that is greater than or equal to half the diameter of the microorganism that is to be killed is used as the sterilization member, and a fluid that contains the microorganism that is to be killed is caused to strike the treatment surface to kill the microorganism that is to be killed.