A liquid injector 1 includes : a living body contact member 3 including a distal-end opening 31 opened at a distal end and a hollow needle 24 having a sharp needle tip 241. The liquid injector also includes: an inner structure body 2 supported movably to a first position where the needle tip 241 is located closer to a proximal-end side than the distal-end opening 31 is and to a second position where the needle tip 241 is projected more to the distal-end side than the distal-end opening 31 to puncture the living body surface while the living body contact member 3 is placed on the living body surface placed on and a regulating member 6 detachably mounted on the inner structure body 2. When the inner structure body 2 moves to the second position from the first position and returns to the first position again, the regulating member 6 is fixed to the living body contact member 3 at the second position, simultaneously separated from the inner structure body 2, and stays at the position to cover at least a part of the vicinity of the distal-end opening 31.
