A human detection system may detect the presence of a human around a shovel by using an image captured by an imaging device that is attached to the shovel and that captures a human from diagonally above. The human detection system may have an extracting part that extracts a part of the captured image as a target image, and an identifying part that identifies whether an image included in the target image extracted by the extracting part is an image of a human by an image processing. A target image region in the captured image corresponds to a virtual plane region having a predetermined size in a real space. In the real space, the virtual plane region faces toward the imaging device and is inclined with respect to a horizontal surface.