Hydrogen is the main constitute of plasmas in HANBIT magnetic mirror device, therefore, measurement of the emission from excited levels of hydrogen atoms is an important diagnostic tool. From the emissivity of H radiation one can derive quantities such as the neutral hydrogen density and the source rate. An unbiased and consistent probability theory based approach within the framework of Bayesian inference is applied to the reconstruction of H emissivity profiles and hydrogen neutral density profiles in HANBIT magnetic mirror device.