This article reviews the studies of light-matter mechanical interaction and its applications. It focuses on the recent trend where the targets of optical manipulation have been shifting to nanoscale objects, where the microscopic light-matter interaction plays an important role. We discuss optical manipulations using light that is resonant with the electronic transitions of nano-objects. The resonant effect is the key mechanism not only for enhancing the exerted force but also for linking the quantum mechanical properties of individual nano-objects to their macroscopic motions.