Every living organism has its own species-specific morphology. Despite the relatively simple ellipsoidal shape of budding yeast cells, the global regulation of yeast morphology remains unclear. In the past, each mutated gene from many mutants with abnormal morphology had to be classified manually. To investigate the morphological characteristics of yeast in detail, we developed a novel image-processing program that extracts quantitative data from microscope images automatically. This program extracts data on cells that are often used by yeast morphology researchers, such as cell size, roundness, bud neck position angle, and bud growth direction, and fits an ellipse to the cell outline. We evaluated the ability of the program to extract quantitative parameters. The results suggest that our image-processing program can play a central objective role in yeast morphology studies.