Provided is an optical probe that can perform low-noise precise OCT measurement even if an object with a high scattering property is measured. The optical probe 20 includes an optical fiber 21 that transmits light between a proximal end 21 a and a distal end 21 b, an optical connector 22 connected with the optical fiber 21 at the proximal end 21 a, a focusing optical system 23 and a deflecting optical system 24 connected with the optical fiber 21 at the distal end 11b, and a support tube 25 and a jacket tube 26 surrounding the optical fiber 21 and extending along the optical fiber 21. The optical fiber 21 includes a core region 41 having a refractive index n1, a first cladding region 42 surrounding the core region and having a refractive index n2, a trench region 43 surrounding the first cladding region and having a refractive index n3, and a second cladding region 44 surrounding the trench region and having a refractive index n4. The refractive indices have a relationship of n1 > n2 > n3 < n4.
