Mental health is important in older age; neighborhood environment is considered a protective factor of depression. Research has established that a critical indicator of neighborhood environment, street connectivity, is related to older people's health. However, little is known about the relationship between street connectivity and depression. We examined the relationship between street connectivity and depression among older people. Using Japan Gerontological Evaluation Study 2013-2016, the target population comprised 24,141 independent older people without depression (Geriatric Depression Scale scores below 5) in 2013. The outcome variable was depression in 2016; the explanatory variable was street connectivity calculated by intersection density and space syntax within 800 m around the subject's neighborhood in 2013. We used logistic regression analysis to calculate the odds ratio and 95% confidence interval for the new occurrence of depression among participants in 2016. This analysis demonstrated incidence of new depression after 3 years that is 17% and 14% lower among participations living in high-intersection density and high-street-connectivity areas, respectively, than those living in low-intersection density and low-street-connectivity areas. The association held after adjusting for physical activities and social interaction. Given the established connection between street connectivity and mental health, the findings can contribute to healthy urban planning.