A syringe pressurization device configured to be attached to a syringe including a barrel and a gasket sliding inside the barrel, the syringe pressurization device comprising: a plunger configured to advance the gasket in a distal end direction; and a grip attachable to the barrel from a direction perpendicular to an axis of the barrel and supporting the plunger, wherein the plunger includes a plunger rod including a screw thread disposed on an outer circumferential surface thereof, and a pressing part disposed at a distal end portion of the plunger rod and configured to press the gasket in a distal end direction, wherein the plunger is a syringe plunger comprising: a rotary operation part disposed at a proximal end portion of the plunger rod, wherein the rotary operation part includes a finger hook rotary operation part protruding in a direction perpendicular to an axis of the plunger rod, and a pinch rotary operation part protruding in a proximal end direction from the finger hook rotary operation part coaxially with the plunger rod, the screw thread is configured to be screwed with a female screwing part, the syringe plunger is configured to advance in a distal end direction by a screwing action between the screw thread and the female screwing part so as to press the gasket in a distal end direction, and an outer diameter of the pinch rotary operation part is smaller than an outer diameter of the finger hook rotary operation part, and wherein said grip includes: a flange attachment part attachable to a flange disposed at a proximal end portion of the barrel, a female screwing part disposed proximal of the flange attachment part and screwed to the screw thread, and an accommodation part disposed between the flange attachment part and the female screwing part and configured to accommodate the pressing part. a plunger configured to advance the gasket in a distal end direction; and a grip attachable to the barrel from a direction perpendicular to an axis of the barrel and supporting the plunger, wherein the plunger includes a plunger rod including a screw thread disposed on an outer circumferential surface thereof, and a pressing part disposed at a distal end portion of the plunger rod and configured to press the gasket in a distal end direction, wherein the plunger is a syringe plunger comprising: a rotary operation part disposed at a proximal end portion of the plunger rod, wherein the rotary operation part includes a finger hook rotary operation part protruding in a direction perpendicular to an axis of the plunger rod, and a pinch rotary operation part protruding in a proximal end direction from the finger hook rotary operation part coaxially with the plunger rod, the screw thread is configured to be screwed with a female screwing part, the syringe plunger is configured to advance in a distal end direction by a screwing action between the screw thread and the female screwing part so as to press the gasket in a distal end direction, and an outer diameter of the pinch rotary operation part is smaller than an outer diameter of the finger hook rotary operation part, and wherein said grip includes: a flange attachment part attachable to a flange disposed at a proximal end portion of the barrel, a female screwing part disposed proximal of the flange attachment part and screwed to the screw thread, and an accommodation part disposed between the flange attachment part and the female screwing part and configured to accommodate the pressing part. a flange attachment part attachable to a flange disposed at a proximal end portion of the barrel, a female screwing part disposed proximal of the flange attachment part and screwed to the screw thread, and an accommodation part disposed between the flange attachment part and the female screwing part and configured to accommodate the pressing part.