A shape detection device includes a flexible insertion section, a curved-shape detection sensor and a flexible exterior tube member arranged in the insertion section. The sensor includes an optical fiber, one or more detecting parts to change characteristics of light propagated by the optical fiber in accordance with a curved shape of the optical fiber, and a light detector. The flexible exterior tube member is arranged in the insertion section to include at least part of the optical fiber, and configured to be curved into a similar shape to the curved shape of the insertion section. The curved-shape detection sensor is partly held and fixed to at least one of the exterior tube member and a distal hold member provided at the distal end of the insertion section.
