There is provided a paste application device which can solve problems of an increased exclusively occupied space attributed to an arrangement of a syringe and of deterioration of a tube.In a paste application unit 15 (a paste application device) for applying a paste 7 stored in a syringe 16 to an application target material, a configuration is adopted in which a pump mechanism 18 for sending the paste 7 under pressure is formed by causing a discharge thread portion 32b provided at a lower portion of a rotary member 32 to rotate about an axis AX within a discharge space 31b provided in a casing portion 31, in which a discharge port 17a, which communicates with the discharge space 31b, is provided at an end portion of the casing portion 31, and in which the syringe 16 is disposed coaxially with the rotary member 32 for detachable connection thereto. By adopting this configuration, the problems can be solved of the increased exclusively occupied space that would occur when the syringe 16 is disposed in parallel to the pump mechanism 18 and of deterioration of the tube.