Anion exchange of NO3-LDH with Br- of KBr, which leads to the formation of Br-LDH and NO3--doped KBr, was found to occur during the preparation of KBr pellets for FTIR measurement, and the obtained spectra were composed of characteristic features of NO3- bands in NO3-LDH and in NO3--doped KBr mixed in variable proportions depending on pellet preparation conditions.