The producing method according to the disclosed technology is a producing method for an organism-derived material into which a bioactive substance has been introduced, the producing method comprising a step of causing a suspension containing the organism-derived material before the introduction of the bioactive substance and containing the bioactive substance to pass through a first electric field region having a first electric field intensity; and a step of causing the suspension to pass through a second electric field region having a second electric field intensity lower than the first electric field intensity after the suspension has passed through the first electric field region. The organism-derived material is a human-derived cell.