[en] We have developed a new method to produce bundles of scintillating micro fibers. It consists in filling a glass capillary with a viscous polymer which is chemically cross-linked to obtain a hard core. Using a polymethylphenylsiloxane (Toshiba XE 5844) doped with a single wavelength shifter, 1-p-anisyl-3-mesityl-2-pyrazolin (PMP 450) at a concentration of 0.006 mol l^-1, we obtained an attenuation length of 70 cm. The scintillation efficiency is similar to a good quality commercial plastic scintillator. ((orig.))