The coated optical fiber (10) includes: an optical fiber (11) including a core (111) and a cladding (112)； a first buffer layer (121) covering the optical fiber (11), and having a refractive index lower than that of the cladding (112) and a Shore D hardness of D/20.0/1 or higher； a second buffer layer (122) covering the first buffer layer (121), and having a higher Shore D hardness than the first buffer layer (121)； and a jacket (13) covering the second buffer layer (122).
