As a plasmonic absorber for short-wavelength infrared hyperspectral imaging, a silicon-coated gold nanodiffraction grating structure is proposed. This plasmonic absorber leads to absorption peaks in short-wavelength infrared region by the high refractive index of silicon coating on gold grating. It is relatively easy to fabricate with smaller size than those of already known absorbers. By performing fabrication, simulation, and measurement, we demonstrate the sharp absorption peaks of short-wavelength infrared light using only 400–1000 nm grating interval. We believe this miniaturized absorber will be able to be applied to hyperspectral imaging without a spectroscope owing to its sharp absorption peak at a specific wavelength.