Beryllium (Be) thin films with superconducting transition temperature (Tc’s) up to about 6 K can be grown on room‐temperature substrates using ion‐beam sputtering. In contrast to the evaporation‐deposited Be grown on a liquid‐helium‐cooled substrate, which is also a superconductor, the ion‐beam‐sputtered Be films show such high thermal stability that theTc’s exhibit no change by room‐temperature annealing for three months.