The efficacy of an antitumor aqueous solution generatable by plasma irradiation varies according to plasma irradiation conditions, and appropriate plasma irradiation conditions depend on the type of tumor. Therefore, the present invention addresses the problem of providing an antitumor aqueous solution manufacturing device whereby an antitumor aqueous solution provided with appropriate antitumor effects can be manufactured. This antitumor aqueous solution manufacturing device (10) for solving the abovementioned problem is a device for manufacturing an antitumor aqueous solution having antitumor effects, wherein the device has a stage (26) for retaining a raw material solution in which a raw material for an antitumor aqueous solution is dissolved, a plasma generating device (20) for generating a plasma to be radiated to the raw material solution retained by the stage (26), a hydrogen peroxide detection sensor (147) for measuring a hydrogen peroxide concentration in the raw material solution, and a control device (38) for controlling the plasma generating device (20), the control device (38) controlling the plasma generating device (20) so that the hydrogen peroxide concentration measured by the hydrogen peroxide detection sensor (147) is within a predetermined range.L'efficacité d'une solution aqueuse antitumorale pouvant être produite par irradiation par plasma varie selon les conditions de l'irradiation par plasma, et les conditions appropriées d'irradiation par plasma dépendent du type de tumeur. Par conséquent, la présente invention cherche à résoudre le problème qui est de fournir un dispositif de fabrication de solution aqueuse antitumorale, à l'aide duquel puisse être fabriquée une solution aqueuse antitumorale présentant des effets antitumoraux appropriés. Ce dispositif de fabrication de solution aqueuse antitumorale (10) qui permet de résoudre le problème présenté ci-dessus est un dispositif permettant la fabrication d'une solution aqueuse antitumorale possé
