A needle device, comprising a needle base and a needle head , the needle base having a first side which is close to skin when using, the needle head having a first end which is connected to the needle base , the needle head extends parallel to the first side , wherein the needle device further comprises: a first structure part , the first structure part is arranged outside the needle base and slip matches with the needle base along extension direction of the needle head , a first limit mechanism is arranged between the first structure part and the needle base , the first limit mechanism is adapted to prevent the first structure part being separated from the needle base along extension direction of the needle head ; a second structure part , the second structure part is arranged outside the first structure part and slip matches with the first structure part along extension direction of the needle head , a second limit mechanism is arranged between the first structure part and the second structure part , the second limit mechanism is adapted to prevent the second structure part being separated from the first structure part along extension direction of the needle head ; the first structure part and the second structure part are adapted to slide along the extension direction of the needle head for holding a second end opposite to the first end into the second structure part ; and the needle base at least comprises an installation portion , the installation portion is a segment of the needle base that may be covered by the first structure part during process of slip match of the first structure part , the first structure part does not exceed first side of the installation portion ; the second structure part has a bottom structure which exceeds the first side of the installation portion ; inner wall of the bottom structure slip matches with the first side of the installation portion . a first structure part , the first structure part is arranged outside the needle base and slip matches with the needle base along extension direction of the needle head , a first limit mechanism is arranged between the first structure part and the needle base , the first limit mechanism is adapted to prevent the first structure part being separated from the needle base along extension direction of the needle head ; a second structure part , the second structure part is arranged outside the first structure part and slip matches with the first structure part along extension direction of the needle head , a second limit mechanism is arranged between the first structure part and the second structure part , the second limit mechanism is adapted to prevent the second structure part being separated from the first structure part along extension direction of the needle head ; the first structure part and the second structure part are adapted to slide along the extension direction of the needle head for holding a second end opposite to the first end into the second structure part ; and the needle base at least comprises an installation portion , the installation portion is a segment of the needle base that may be covered by the first structure part during process of slip match of the first structure part , the first structure part does not exceed first side of the installation portion ; the second structure part has a bottom structure which exceeds the first side of the installation portion ; inner wall of the bottom structure slip matches with the first side of the installation portion . <EOS>