An applicator comprising: a cylindrical syringe molded from a resin material and having two ends, the cylindrical syringe including a cartridge fitting portion at one of the two ends of the cylindrical syringe, the cartridge fitting portion being configured to be fitted with a cartridge which includes a cylindrical portion having two ends and an opening portion formed at one of the two ends of the cylindrical portion, a nozzle portion provided at the other of the two ends of the cylindrical portion, and a piston disposed inside the cylindrical portion to push out a content contained in the cylindrical portion from the nozzle portion; and a plunger molded from a resin material and having two ends, the plunger including a pressing portion provided at one of the two ends of the plunger and configured to be inserted into the cylindrical syringe from the other of the two ends of the cylindrical syringe and to press the piston inside the cartridge fitted with the cartridge fitting portion, and an operated portion provided at the other of the two ends of the plunger, extending through the other end of the cylindrical syringe, and configured to be pressed by a finger of an operator, characterized in that: the applicator further comprises a resistance structure (54, 75) provided between an inner peripheral surface of the cylindrical syringe and an outer peripheral surface of the pressing portion of the plunger, the resistance structure being configured to act as resistance to movement of the pressing portion when the pressing portion is moved toward the cartridge fitting portion beyond a predetermined position and to movement of the pressing portion when the pressing portion is moved from the side of the cartridge fitting portion toward the other end of the cylindrical syringe beyond the predetermined position, wherein the resistance structure (54, 75) is configured to allow the pressing portion to be moved beyond the predetermined position against the resistance when a force equal to or greater than a predetermined force is applied to the plunger in a longitudinal direction of the plunger. a cylindrical syringe molded from a resin material and having two ends, the cylindrical syringe including a cartridge fitting portion at one of the two ends of the cylindrical syringe, the cartridge fitting portion being configured to be fitted with a cartridge which includes a cylindrical portion having two ends and an opening portion formed at one of the two ends of the cylindrical portion, a nozzle portion provided at the other of the two ends of the cylindrical portion, and a piston disposed inside the cylindrical portion to push out a content contained in the cylindrical portion from the nozzle portion; and a plunger molded from a resin material and having two ends, the plunger including a pressing portion provided at one of the two ends of the plunger and configured to be inserted into the cylindrical syringe from the other of the two ends of the cylindrical syringe and to press the piston inside the cartridge fitted with the cartridge fitting portion, and an operated portion provided at the other of the two ends of the plunger, extending through the other end of the cylindrical syringe, and configured to be pressed by a finger of an operator, characterized in that: the applicator further comprises a resistance structure (54, 75) provided between an inner peripheral surface of the cylindrical syringe and an outer peripheral surface of the pressing portion of the plunger, the resistance structure being configured to act as resistance to movement of the pressing portion when the pressing portion is moved toward the cartridge fitting portion beyond a predetermined position and to movement of the pressing portion when the pressing portion is moved from the side of the cartridge fitting portion toward the other end of the cylindrical syringe beyond the predetermined position, wherein the resistance structure (54, 75) is configured to allow the pressing portion to be moved beyond the predetermined position against the resistance when a force equal to or greater than a predetermined force is applied to the plunger in a longitudinal direction of the plunger. the applicator further comprises a resistance structure (54, 75) provided between an inner peripheral surface of the cylindrical syringe and an outer peripheral surface of the pressing portion of the plunger, the resistance structure being configured to act as resistance to movement of the pressing portion when the pressing portion is moved toward the cartridge fitting portion beyond a predetermined position and to movement of the pressing portion when the pressing portion is moved from the side of the cartridge fitting portion toward the other end of the cylindrical syringe beyond the predetermined position, wherein the resistance structure (54, 75) is configured to allow the pressing portion to be moved beyond the predetermined position against the resistance when a force equal to or greater than a predetermined force is applied to the plunger in a longitudinal direction of the plunger.