© 2018 World Association for Disaster and Emergency Medicine.Introduction The Health Belief Model (HBM) can be used as a guide in enhancing the peoples' awareness, improving the motivation, and providing tools that address beliefs and attitudes toward general disaster preparedness (GDP).Methods The aim of this study was to improve and re-test all psychometric properties of the published General Disaster Preparedness Belief (GDPB) scale based on HBM carried out in the general population. This scale development study measured by 58 items was prepared under the same structure of the developed GDPB scale that measured 31 items before. This expanded scale was applied to 973 individuals. Firstly, the data from application of the expanded scale was examined under Exploratory Factor Analysis (EFA). Then, the estimations obtained from Confirmatory Factor Analysis (CFA) for the expanded scale with 45 items were compared with the estimations obtained from the previous scale with 31 items.Results The EFA lead to the removal of 13 items and the retention of 45 items. The items which the factor loadings were below 0.30 and which gave the factor loadings for more dimension were excluded from the data set. A model measured six dimensions with 45 items was hypothesized: Six items under perceived susceptibility, four items under perceived severity, six items under perceived benefits, 14 items under perceived barriers, five items under cues to action, and 10 items under self-efficacy. For CFA results, all estimations for factor loadings were significant. The scale with 45 items obtained in this study fit because Comparative Fit Index (CFI), Goodness of Fit Index (GFI), and Adjusted Goodness of Fit Index (AGFI) were over 0.95.Conclusion These results suggest that the scale with 45 items shows improvement in the scale with 31 items. This study indicates that the GDPB scale with 45 items based on HBM has acceptable validity and reliability. This tool can be used in disaster preparedness surveys.