A preheating device for endoscopy includes a flexible bag, a plurality of first welded joint, and a mark member. The flexible bag is disposed with a saturated sodium acetate solution and a trigger. The flexible bag includes a closed circumference around the outer periphery thereof. The closed circumference includes a longer side and a shorter side next to each other. The plurality of the first welded joint is arranged into a folding line along a longitudinal direction, wherein every two adjacent first welded joints of the folding line forms a flowing space. The folding line is substantially parallel to the longer side. The first welded joint nearest to the shorter side is the last first welded joint, and the mark member is disposed on the flexible bag between the last first welded joint and the shorter side. The mark member is used for indicating a placement of an endoscopy.一種內視鏡預熱裝置，包括可撓袋體、複數熔著點及標記件。可撓袋體內容設有飽和醋酸鈉溶液與啟動件，可撓袋體包括封閉週緣以圍繞於其外週，封閉週緣包括彼此相鄰之長邊及短邊。複數熔著點沿縱長方向排列成一折線，折線上相鄰的兩熔著點之間具有易於流動空間，折線實質上平行於長邊，折線最鄰近於短邊的熔著點為一最末熔著點。標記件設置於可撓袋體上並介於最末熔著點與短邊之間，標記件用以指示內視鏡的擺放位置。
