Distinct InSb/InAs quantum nano-stripes possessing type-II band alignment with a broken gap are grown using molecular beam epitaxy with low substrate temperature and slow growth rate, aiming for light emission in a mid-infrared range. The quantum nano-stripes are shown to emit light at a wavelength of 3.1 mu m. The excitation power dependence of photoluminescence spectra from the quantum nano-stripes reveals a clear linear blueshift with the third root of the excitation power, which is a unique property of the quantum nanostructures with type-II band alignment. The demonstrated mid-infrared light emission from the InSb/InAs quantum nano-stripes would offer a promising pathway for realizing practical, highly-efficient, and room-temperature-operating mid-infrared light sources and detectors.