An optical fiber for an optical fiber sensor and a chemical sensor using the same are disclosed. The optical fiber includes a core area, and a suspended cladding area formed around the core area and having at least one cladding hole. The core area has at least one core hole for reducing an effective refractive index of the core area. The optical fiber and the chemical sensor using the same may have improved measurement sensitivity by increasing an evanescent field fraction of existing suspended core fibers.