1. A cell-image analyzing apparatus comprising: a cell imaging system having an imaging optical system and an image sensor, for imaging cells that exist in a vessel; and a cell-image analyzer for automatically analyzing a predetermined characteristic quantity on the cells using a cell image captured via the cell imaging system, upon delimiting cell regions; wherein the cell-image analyzing apparatus has a cell-contour emphasizing system for automatically emphasizing contour portions of images of the cells that exist in the vessel, which is arranged at a shot position of the cell imaging system.