A fiber optic mechanical splicer includes a fiber connection base, a base cover and one or more fastening clamps. The base includes a plurality of insertion parts, fiber connection parts, and auxiliary protuberances. Each of the insertion parts having an insertion hole through which an optical cable is inserted. A connection groove is formed at a central portion of the fiber connection parts and extends in a lengthwise direction of the fiber connection parts. The base cover covers the fiber connection parts and is supported by the auxiliary protuberances. The one or more fastening clamps elastically fit around the fiber connection base and the base cover to fixedly hold the fiber connection base and the base cover with each other while pressing the optical fiber seated in the connection groove.