An injection needle apparatus in which an operation for relatively moving an outer tube 4 and an inner tube 5 is performed to project and retract a needle body 12 from and into a distal end of the outer tube 4, and to carry out a movement of rotation of the needle body 12 at a predetermined angle by relative forward and backward movements of the outer tube 4 and inner tube 5 in their longitudinal directions every time the forward and backward movement operations is repeated, thereby enabling changing a direction of a needlepoint 14 of the needle body 12 at each angle.