The present invention provides an antibacterial layer-attached base material which has excellent light resistance and includes an antibacterial layer exhibiting an antibacterial action within a short period of time, an antibacterial sheet, a radiation photographing device, and a touch panel. The antibacterial layer-attached base material of the present invention is an antibacterial layer-attached base material including: a base material; and an antibacterial layer which is disposed on at least a part of the surface of the base material, in which the antibacterial layer contains at least one antibacterial agent containing silver, and the amount of silver ions per a unit area measured in an extraction test is 15 to 50 ng/cm2.