White light emitting diode (LED) lighting is being used more frequently for illumination in recent years. The coupling of blue with yellow emitting phosphors produces white LED light. Blue light has a short wavelength in the visible light spectrum and exerts a strong influence on photobiological functions. Cycling light exposure is necessary for the synchronizing the circadian rhythm. The exposure to white light at subjective nighttime induces cognitive impairment, depression, and anxiety by disturbing the circadian rhythm and increasing stress hormone. However, few studies have been performed at the subjective daytime. Thus, the aim of this study was to determine whether exposure to blue light from an LED at subjective daytime affects brain function. We irradiated C57BL/6J mice with 200 lux of blue LED light for 12 h/day for 6 weeks at the subjective daytime and performed Y-maze, object recognition, tail suspension, and open field tests. There was no significant difference between the exposed mice and control mice. Histological analysis of the retina showed that the blue light exposure did not alter the retinal thickness. We conclude that the exposure to blue LED light at subjective daytime does not affect the retinal morphology or brain function in pigmented mice.