A cell-image analyzing apparatus is intended to analyze, using a cell image, a cell collective that forms a colony, and is provided with a computer. The cell-image analyzing apparatus has an image analysis software that makes the computer function as: a boundary element extracting means for extracting boundary elements of subjects upon analyzing the cell image; a possible colony region determining means for determining, as a possible colony region, a region surrounded by boundary elements of subjects and having a size greater than a first criterion value; and a colony region determining means for determining, in the possible colony region, a region containing more than a predetermined number of clustered regions each being surrounded by boundary elements of subjects and having a size smaller than a second criterion value, as a colony region.