From the emission line map in Hα over the full face of the spiral galaxy NGC 3359, we analyze the internal velocity structure of the H II region population. The emission line profiles show central peaks, with turbulent velocity widths of <=20 km s-1, and also broad shallow wings, with typical velocities of ˜ 50 km s-1, with respect to the rest velocity of the H II region. We verify the identification of these wings as due to expanding gas, quantify the energy involved, and suggest physical models for their interpretation, as the effects of mechanical and radiative outflows from the central OB stellar cluster.