It is known that there is a marked variation in the frequency of variant angina attacks according to the circadian rhythm. The attack frequency is usually highest in the early morning and lowest in the afternoon. We describe here a middle-aged woman with variant angina whose chest pain occurred only during daytime. Because of her job, she sleeps from noon to 6 pm, and she experienced chest pain only during 2 to 3 pm. These findings suggest that the alterations to the sleep and wake cycle can affect the circadian variation of variant angina.