Needle head assembly and injection hand tool

The utility model discloses a needle head assembly which comprises an upper cover, a first through hole is formed in the upper top face of the upper cover, a receding box is arranged on the inner top face of the upper cover, and a second through hole is formed in the lower bottom face of the receding box. The lower cover is in threaded connection with the upper cover, an inner cavity of the upper cover and an inner cavity of the lower cover jointly form a containing cavity, a partition plate is arranged in the lower cover, and a plurality of needle outlet holes are formed in the partition plate; the needle outlet module comprises a connecting part, a main body part and a needle outlet part which are sequentially connected from top to bottom, the main body part is located in the containing cavity, the connecting part extends upwards and sequentially penetrates through the second through hole and the first through hole, the connecting part is provided with a limiting plate, the limiting plate is located in the