In an optical fiber array, an optical fiber, a bundle of optical fibers or an optical fiber ribbon is mounted on an array substrate with a V-groove or V-grooves. A bare fiber portion in which a fiber coating is removed is placed in the V-groove, pressed by a presser member 6 and bonded by adhesives. At the front end, the fiber(s) is/are accurately positioned to connect to optical components or PLCs. The bare fiber portion contains a spliced portion of the dissimilar optical fibers having different mode field diameters and a mode field converting portion. The spliced portion of the dissimilar optical fibers is mounted on the array substrate. A flexible protection member is provided in the fiber coating portion extending over a rear edge of the array substrate. The optical fiber is bonded onto the array substrate, employing three kinds of adhesives that are different in the Young's modulus after hardening and the viscosity before hardening.