To clarify the relationship between smartphone addiction and headaches, we conducted a questionnaire survey of women who were aware of having headaches. A questionnaire survey was conducted on the Internet of 600 women between the ages of 20 and 40 who had suffered from headaches in the past three months. The subjects were divided into a smartphone addiction group (n = 120) and a smartphone non-addiction group (n = 480). The addiction group had more complaints of photophobia and phonophobia, which are accompanying symptoms of headaches, and the impact of headache attacks on daily life was greater than the non-addiction group. There was no significant difference in sleep time between the groups, but the addiction group used their smartphones longer on average and felt more sleepy during the day. More respondents in the addiction group complained of decreased visual acuity, dry eyes, and blurred vision than the non-addiction group, suggesting that blue light from computers and smartphones affected their eyes. Moreover, the frequency of headaches, stiff shoulders, fatigue, sleeping disorders, hormonal imbalance, and dark circles and wrinkles around the eyes were higher in the addiction group compared to the non-addiction group. Although smartphone addiction has not been established as a disease, our findings suggest that it reduces sleep quality and worsens headaches.