A cutting device for cutting an optical fiber running in a first direction includes a supporting piece having a free end and a fixed end and having resilience, a cutting blade supported by the supporting piece that comes into contact with the optical fiber to make a right angle with the optical fiber at a point of the contact, and a driving device. The driving device is configured to press the supporting piece in a second direction in a plane perpendicular to the first direction, with the second direction not intersecting with the first direction.