Disclosed are a sleeve for abutting, aligning, and retaining opposed optical connector ferrules and methods for the production thereof. The sleeve has a tubular body provided at three points on the inner wall surface thereof with ridges of an arcuate cross section extending from one to the other end of the tubular body in the longitudinal direction thereof and a slit formed therein in the longitudinal direction thereof. The sleeve is formed of an amorphous alloy possessing at least a glass transition region, preferably a glass transition region of not less than 30 K in temperature width. Preferably the sleeve is formed of an amorphous alloy having a composition represented by the following general formula and containing an amorphous phase in a volumetric ratio of at least 50%: XaMbAlc wherein X represents either or both of two elements, Zr and Hf, M represents at least one element selected from the group consisting of Mn, Fe, Co, Ni, and Cu, and a, b, and c represent such atomic percentages as respectively satisfy 25≦a≦85, 5≦b≦70, and 0