The invention provides a fixing device for fixing at least one object to be fixed on a bearing body. The fixing device comprises at least one positioning part, a fixing plate fixed on the bearing body, and a pressure plate combined with the fixing plate through the positioning part, wherein the pressure plate is provided with at least one fixed connection part and a baffle arranged corresponding to the fixing plate; the baffle is used for supporting against one side edge of the object to be fixed to restrict the object to be fixed to move along a first direction; and the positioning part can be movably inserted into the fixed connection part to ensure that the pressure plate can selectively move along the first direction and be positioned on the fixing plate to regulate the distance between the baffle and the fixing plate.