A device enables the more stable performance of uniform treatment such as reaction by reducing pulsation generated in a fluid introduced between treatment surfaces using a micropump effect. The device treats an object between treatment surfaces. The treatment is performed by introducing a fluid between the treatment surfaces using a micropump effect. The micropump effect generates force in the direction in which the treatment surfaces move away from each other by the rotation of a treatment part and the recessed section formed in the treatment surface to thereby produce the effect of introducing the fluid between the treatment surfaces. The recessed section is formed so as to extend in the circumferential direction and inward/outward direction of the treatment surface, and multiple recessed sections are provided or an additional recessed section (α) different from the recessed sections is formed in at least one of the treatment surfaces.
