Disclosed are a barb-wired single crystalline silicon micro needle and a biopsy method and a medicine injecting method using the same. The micro needle comprises a main body part, at least one extension part formed on a side surface of the main body part, and a protrusion part protruded from both side surfaces of the extension part. A medicine storage is formed on a surface of the main body part. A fluid passage is formed in the extension part and the main body part. It is easy to pick the tissue sample with the protrusion part just by inserting and extracting the extension part of the micro needle into and from the tissue for a biopsy. Therefore, the biopsy procedures can be simplified. In addition, the medicine in the storage can be injected into the tissue via the fluid passage.