A shield structure for electron beam sterilization equipment. The shield structure satisfies at least one of the following conditions: (I) an outer diameter D4 of an internal circumferential shield S4 is larger than an outer diameter D5 of an internal circumferential shield S5, and (II) an internal circumferential shield ST2 of a circular path LT2 downstream of an entrance trap zone Z1 connected to an outer-surface sterilization zone Z2 has an outer diameter DT2 that is larger than an outer diameter D1 of an internal circumferential shield S1 of a circular path L1 upstream of the outer-surface sterilization zone Z2.