1. A particle image analyzing apparatus for analyzing an image of a particle, the particle image analyzing apparatus comprising: an illuminating unit for providing dark field illumination a particle; an imaging unit for capturing an image by imaging the illuminated particle; and an image processing unit for extracting a particle image from the image captured by the imaging unit based on a threshold value larger than a luminance value substantially corresponding to the background of the particle image, and analyzing the extracted particle image to obtain morphological feature information indicating the morphological feature of the particle.