An electron beam cap-sterilizer radiates an electron beam onto caps while the caps are continuously conveyed. The caps are conveyed in the restricting conveying section while the movements of the caps are restricted, so that the caps roll down freely and separately from each other in the free conveying section. The electron beam radiating device emits electron beams onto the inside of the caps in the lateral direction while the caps are conveyed in the free conveying section. A deflecting device is provided in the free conveying section. The deflecting device is located at the opposite side of the electron beam radiating device to deflect the electron beams emitted by the electron beam radiating device onto the outside of the caps.
