契約文件包括廣生行與外地銷售代理所簽訂的合約、土地樓舖買賣租賃契據，及1910年至1935年間官方簽發給廣生行的商標註冊證、商標登錄證及批文等的原件。這批共39張的證書，每張代表廣生行個別產品的商標及標誌已取得專利，以防止被仿冒。此外，文件亦包含分行一宗訟案的法院判決書、代銷貨擔保書、驗貨證明文件、保險單和收據、借據等。檔案保存了廣生行一本厚厚的自製相片冊，內容包括廣生行各類產品、商標圖樣、商業執照、證書、獎狀、賀幅、各省縣警誡商標影射售偽貨公告、產品化驗報告、廣告、廣生行店舖、工場、生產流程等的相片複本，涵蓋1909－1926年的時期。

This subseries contains a variety of legal documents including contracts signed between Kwong Sang Hong and its sales agents outside Hong Kong, contracts for the sales of land and properties, tenancy agreements, etc. Also included herein are original trademark registration certificates and approval papers issued by official authorities between 1910 and 1935. There are a total of 39 such certificates, each represents successful registration of the trademark and logo of individual product of Kwong Sang Hong to protect against imitation. Other documents include court decision paper on a dispute case, guarantee letters for sales agents, official verification paper of goods, insurance policy and receipts, money lending slips, etc. Specially kept in this subseries is a thick custom-made album containing a large collection of duplicated copies of the photos of Kwong Sang Hong products, trademark samples, business licences, certificates, awards, government announcements, laboratory test reports, advertisements, branch stores and workshops, factory production process and so on, covering a period from 1909 to 1926.