An injection needle unit is disclosed usable in a portable automatic syringe device, the injection needle unit comprising a feeding tube, an "L"-shaped injection needle member connected to one end of the feeding tube, a connector connected to the other end of the feeding tube, and a depressing member integrally formed with the injection needle member in such a fashion that the injection needle protrudes perpendicularly from the depressing member, the depressing member being depressed against the skin of a user upon penetrating the injection needle member into the subcutaneous tissue of the user. The injection needle member comprises a vertical injection needle provided with a needle tip; a horizontal connecting rip fitted in the one end of the feeding tube, and a curved portion connected between the injection needle and the connecting rib in such a fashion that it has a quadrant shape extending circumferentially about a center, flush with an upper end of the injection needle, said curved portion having a downward slant portion connected to the connecting rip. The curved portion of the injection needle member is capable of absorbing an impact, thereby preventing a breakage of the injection needle member.