The photoelastic sensitivities of ultraviolet (UV)-curable resins irradiated to UV radiation for different times were measured using a photoelastic technique. The liquid UV-curable resins poured in the pocket (55 mm long, 5 mm wide and 3 mm thick) of an acrylic mold were irradiated to UV radiation for 45 s to 960 s. The specimens (50 mm long, 5 mm wide and 3 mm thick) were cut from the resins irradiated for different times. The specimens placed in a circular polariscope were subjected to four-point bending using a universal test machine. The photoelastic sensitivity for each specimen was determined through the use of the relationship between the orders of isochromatic fringes appearing at the upper and lower edges of the specimen as the bending load increased and the loads at which their fringes appeared during the bending test. The photoelastic sensitivities were approximately constant regardless of UV radiation time.