A sheet material adhesive agent application method comprising: performing a first action sequentially for multiple sheet materials stacked in a case of a sheet material stocker (3A,3B), wherein the first action includes: taking out an uppermost one of the multiple sheet materials by a sheet material take-out means; transferring the taken-out sheet material to an adhesive agent application stage; and applying an adhesive agent to the transferred sheet material at the adhesive agent application stage; and performing a second action for a first one of the sheet materials in advance to the application of the adhesive agent to the first sheet material, wherein the second action includes setting the first sheet material so that the first sheet material has a predetermined curvature, characterized in that performing the second action under a condition that the first sheet material is stacked in the sheet material stocker (3A,3B), the second action is implemented by setting an uppermost group of sheet materials of the multiple sheet materials so that each sheet material of the uppermost group has a curvature projecting upward, wherein the uppermost group includes the uppermost sheet material, the second action is implemented so that the curvature of each sheet material of the uppermost group is greater than that of another sheet material immediately below the each sheet material, wherein the application of the adhesive agent is implemented by spraying the adhesive agent to the transferred sheet material by an application gun at the adhesive agent application stage; and the application of the adhesive agent at the adhesive agent application stage is completed before the first sheet material is restored to a state before the second action. performing a first action sequentially for multiple sheet materials stacked in a case of a sheet material stocker (3A,3B), wherein the first action includes: taking out an uppermost one of the multiple sheet materials by a sheet material take-out means; transferring the taken-out sheet material to an adhesive agent application stage; and applying an adhesive agent to the transferred sheet material at the adhesive agent application stage; and performing a second action for a first one of the sheet materials in advance to the application of the adhesive agent to the first sheet material, wherein the second action includes setting the first sheet material so that the first sheet material has a predetermined curvature, characterized in that performing the second action under a condition that the first sheet material is stacked in the sheet material stocker (3A,3B), the second action is implemented by setting an uppermost group of sheet materials of the multiple sheet materials so that each sheet material of the uppermost group has a curvature projecting upward, wherein the uppermost group includes the uppermost sheet material, the second action is implemented so that the curvature of each sheet material of the uppermost group is greater than that of another sheet material immediately below the each sheet material, wherein the application of the adhesive agent is implemented by spraying the adhesive agent to the transferred sheet material by an application gun at the adhesive agent application stage; and the application of the adhesive agent at the adhesive agent application stage is completed before the first sheet material is restored to a state before the second action. taking out an uppermost one of the multiple sheet materials by a sheet material take-out means; transferring the taken-out sheet material to an adhesive agent application stage; and applying an adhesive agent to the transferred sheet material at the adhesive agent application stage; and performing a second action for a first one of the sheet materials in advance to the application of the adhesive agent to the first sheet material, wherein the second action includes setting the first sheet material so that the first sheet material has a predetermined curvature, characterized in that performing the second action under a condition that the first sheet material is stacked in the sheet material stocker (3A,3B), the second action is implemented by setting an uppermost group of sheet materials of the multiple sheet materials so that each sheet material of the uppermost group has a curvature projecting upward, wherein the uppermost group includes the uppermost sheet material, the second action is implemented so that the curvature of each sheet material of the uppermost group is greater than that of another sheet material immediately below the each sheet material, wherein the application of the adhesive agent is implemented by spraying the adhesive agent to the transferred sheet material by an application gun at the adhesive agent application stage; and the application of the adhesive agent at the adhesive agent application stage is completed before the first sheet material is restored to a state before the second action.