A disposable needle hair transplanter includes: a plunger structure having an outer barrel defining a passage, a plunger assembly having at least one push needle movable within the passage of the outer barrel, and a hair transplantation depth controller drivingly connected with the plunger assembly via a link; a needle having a needle seat connected with the outer barrel and at least one needle tube in which a hair follicle is loadable, the hair transplantation depth controller serving to restrict the depth by which the needle tube is thrust into the scalp; and a hair follicle depth controller having a cylindrical structure fitted around the needle seat and a shaft tube connected with the cylindrical structure and coaxially disposed around the needle tube. The hair transplantation depth controller is disposed around the shaft tube and movable along the shaft tube toward or away from the scalp.