To provide a bismuth based glass composition with crystallinity which does not reflow during the heat treatment after crystallization, for example, vacuum discharge process, and further does not increase heat expansion coefficient after crystallization.

The bismuth-based glass composition with crystallinity comprises a glass component containing Bi2O3, B2O3 and ZnO and yields a crystal having a heat expansion coefficient of at most 10010-7/C when burned at a temperature in the range of 450-550C for 30 minutes.