The purpose of this study was to evaluate the effect of light irradiation through the outer surface of a CAD/CAM composite resin crown on the initial bond strength of a dual-cure resin cement. A CAD/CAM composite resin block was cut to a thickness of 2 mm as a specimen, and the surface was treated with phosphoric acid and silane coupling agent. Adherend for the shear bond strength test made of silver-palladium-copper-gold alloy was bonded to the specimen with dual-cure resin cement. Assuming a clinical situation, the specimen was irradiated by dental curing light 5 minutes after the bonding procedure. A total of 90 specimens were divided into three groups: group without light irradiation, group with light irradiation for 3 seconds, group with light irradiation for 20 seconds. Half of the specimens in each group (n = 15) were measured for shear bond strength after 1 hour, and the remaining half (n = 15) were measured after 24 hours according to ISO/TR 11405. As a result, the bond strength of the group with light irradiation for 20 seconds was significantly higher than that of the other two groups at 1 hour after the bonding procedure. There was no significant difference in bond strength between all groups at 24 hours after the bonding procedure. There was no significant difference between the bond strength after 1 hour of the group with light irradiation for 20 seconds and the bond strength after 24 hours of all groups. It was shown that high initial bond strength can be obtained by irradiating light for a sufficient time when luting a CAD/CAM composite resin crown.