A parameter-based survey of the synthesis conditions by a so-called pressureless consolidation method to fabricate glass-bonded sodalite waste form for stabilizing fission products generated in pyrometallurgical reprocessing of spent metal fuel was performed. The maximum temperature, the heating duration at the maximum temperature, the glass fraction in the initial material, and the weight load used for pressing the material were chosen as the variable parameters. Accordingly, modified conditions to reduce the maximum temperature and increase the weight load were selected for reducing the volatilized-salt ratio during the heating and the free-salt ratio in the product. By fabricating a simulated waste under the modified conditions, the effect of changing the conditions was confirmed. Leaching tests in pure water using the consolidated products fabricated under both reference and modified conditions showed that the stability of the products was not significantly deteriorated by modifying the heating conditions.