Some studies have shown that pleasant scent encourages the prosocial behavior of people requested for help. However, the effect of pleasant ambient odor on spontaneous helping has never been tested. Male and female confederates accidentally dropped a glove on the floor while walking in places with pleasant ambient odors (e.g., pastries) and in places with no odor. The confederate continued his/her walk, seemingly unaware of his/her loss. It was found that passers-by helped the confederates more favorably in the pleasant-smelling areas. Positive mood induced by ambient smell was used to explain such results.