A food processing device includes: a reaction vessel (1); a stirrer (2) including a stirring body (4) that rotates to stir a reaction product in the reaction vessel (1); and catalyst reactors (6). Each of the catalyst reactors includes a reaction tube (7) and a light source (8) disposed in the reaction tube. The reaction tube has an outer surface on which a photocatalyst is provided. The reaction tube transmits light emitted from the light source. The catalyst reactors are arranged around a rotating shaft (3). The light source includes light emitters (12) disposed at different positions. When viewed in an axial direction of the rotating shaft, the catalyst reactors have phases equal to each other. The phase of each of the catalyst reactors is a phase of a reference direction of the reaction tube of the catalyst reactor with respect to a straight line (L1) connecting centers of the rotating shaft and the reaction tube. When viewed in the axial direction of the rotating shaft, the reference direction of the reaction tube is a direction determined on the basis of a direction in which light is emitted from the light emitters disposed in the reaction tube and a positional relationship between the light emitters.