A drug injection syringe that has a reduced dead volume to reduce an amount of remaining drug and can efficiently inject a small amount of drug into a body without leakage is provided. A drug injection syringe 1 includes an injection needle assembly 50 including a needle hub 80 for supporting an injection needle 90, an elastic body 70 mounted on the needle hub 80, the injection needle 90 being inserted in the elastic body 70, and a fitting sleeve 60 accommodating the needle hub 80 and the elastic body 70 and including an opened fitting hole 61 having a female taper 63, and a syringe body 10 including an outer tube 30 for containing drug 31 in a sealed manner and a drug discharge tube 40 having a male taper 43 that fits into the female taper 63, the syringe body 10 and the injection needle assembly 50 being coupled together by pushing the drug discharge tube 40 into the fitting hole 61 by press fitting. The elastic body 70 has a pocket 73 opening to a contact surface that makes contact with a distal end of the drug discharge tube 40, and couples together the drug discharge tube 40 and the injection needle 90 in a liquid-tight manner by compressively deforming, by the press fitting, at a protruding portion 72 provided on a periphery of the pocket 73 to stretch against an inner wall of the fitting hole 61, thereby providing liquid-tightness.