To provide an optical fiber arranging member which can transform different mode field shapes into suitable shapes for collectively and easily connecting a plurality of optical fibers to an optical part.

An optical fiber arranging member 1 has a plurality of first optical fibers 2 arranged in parallel, a arranging member 5 which arranges and holds the first optical fibers 2 in parallel, second optical fibers 4 to be connected to the tip parts of the first optical fibers 2, respectively, and connecting parts 6 of the first optical fibers 2 and the second optical fibers 4 located on the arranging member 5. The first optical fiber 2 and the second optical fiber 4 have a different mode field shape, respectively. The optical fiber arranging member 1 has a mode field transforming part to bring a different mode field shapes mutually coincided near the connecting parts 6 (or the first optical fiber 4 side or the second optical fiber 4 side).