An object of the present invention is to provide a guidewire having high safety and improved flexibility and rotation followability, and capable of directing a catheter with ease. A guidewire of the present invention has an inner coil that surrounds a distal side portion of a core shaft, and an outer coil that surrounds the inner coil and the distal side portion of the core shaft. The core shaft has a second flat part in flattened shape in substantially contact with an inner peripheral surface of the inner coil. With this configuration, the distal side portion of the guidewire is protected by a double coil structure, while having high torsional stiffness. This leads to improvement in safety and rotation followability, while allowing a catheter to be directed with ease.
