An optical system, imaging device and high-resolution processing method precisely generate a high-resolution image by using image data with few pixels. The optical system images an optical image in an imaging unit, the imaged image is spatially discretized so as to be sampled and converted into an image signal, thereby being recorded in a recording unit. A timing at which the image is imaged by the imaging unit is recorded in an imaging timing recording unit. A weight coefficient for the image is calculated by a weight calculating unit by utilizing the timing information obtained by the imaging timing recording unit. A high-resolution processing unit generates a high-resolution image by using the weighted information of the image generated by the weight calculating unit.