This paper aims to clarify the impact of the Great Kanto Earthquake in pre-war Japan on the accounting behaviour of companies. Prior research dealing with the relationship between the Great Kanto Earthquake and accounting in pre-war Japan has been limited to the individual company level, and the overall reality has not been clarified. Based on 272 business reports issued by 22 companies （in the machinery industry） between 1921 and 1928 held at the Japan Digital Archives Center, we investigated whether companies disclosed items concerning depreciation expenses in their business reports, and whether depreciation rates changed before and after the earthquake. The results showed that the level of disclosure of depreciation expenses declined after the earthquake. This suggests that the external shock of the earthquake had a certain impact on the accounting behaviour of several companies in terms of depreciation.