We propose a flexible intra-fascicular nerve electrode for control of an artificial heart fabricated by micro machining techniques. We have studied methods for the control of an artificial heart by using autonomous nerve information. Though several approaches have been reported for chronic measurements from peripheral nerves, stable and long-term measurements from autonomous nerves have not yet been established. In order to realize stable and low-invasive measurements, we focused on the electrode's flexibility. Our electrode is fabricated on a flexible polyimide film using micro machining techniques. The electrode consists of four needle-shaped flexible probes. After the planar patterning process, the tips of each probe are bent perpendicularly for insertion into the nerve bundle. The recording sites are placed on the tips of the each probe for the purpose of contacting nondamaged nerve areas. Also the hook-shaped structures are fabricated near the tips to avoid tips and nerve bundle shifting. As a result of preliminary experiments, the thickness of the film that is able to be inserted into the vagal nerve bundle of goat is 75 μm. As a first step for the evaluation for the electrodes, we were able to successfully measure neural activities of the sciatic nerve bundle of rats.