Fiber components form the standard not only in modern telecommunication but also for future quantum information technology. For high-performance single-photon detection, superconducting nanowire single-photon detectors (SPDs) are typically fabricated on a silicon chip and fiber-coupled for easy handling and usage. The fiber-to-chip interface hinders the SPD from being an all-fiber device for full utilization of its excellent performance. Here, we report a scheme of SPD that is directly fabricated on the fiber tip. A bury-and-planar fabrication technique is developed to improve the roughness of the substrate for all-fiber detectors’ performance for single-photon detection with amorphous molybdenum silicide (MoSi) nanowires. The low material selectivity and universal planar process enable fabrication and packaging on a large scale. Such a detector responds to a broad wavelength range from 405 nm to 1550 nm at a dark count rate of 100 cps. The relaxation time of the response pulse is ~ 15 ns, which is comparable to that of on-chip SPDs. Therefore, this device is free from fiber-to-chip coupling and easy packaging for all-fiber quantum information systems.