A bacteria analyzer for analyzing bacteria contained in a specimen, comprising: a detector comprising: a light source for irradiating light on a measurement sample prepared from a specimen and a reagent; and a light receiving unit for receiving a scattered light and a fluorescence which are generated from the bacteria present in the measurement sample irradiated with light from the light source; a control unit configured to read out measurement data, wherein the control unit is configured to generate a two-dimensional scattergram on which the measurement data are plotted based on the scattered light and the fluorescence; wherein the control unit is configured for: (a) counting a number of bacteria contained in a plurality of regions (D0,..., D3) on the scattergram, the plurality of regions (D0,..., D3) being regions divided at radially equal angle with an origin of the scattergram as a center; (b) generating frequency distribution data for generating a frequency distribution graph which has as parameters the number of bacteria and distribution position of bacteria in each region of the plurality of regions (D0,...,D3), wherein the distribution position of bacteria comprises a radial angle of each region from the origin of the scattergram; and (c) determining a form of the bacteria contained in the measurement sample based on a region in which the number of bacteria is a peak of the frequency distribution data, wherein the form of the bacteria and the radial angle of each region are assigned based on experimental data. a detector comprising: a light source for irradiating light on a measurement sample prepared from a specimen and a reagent; and a light receiving unit for receiving a scattered light and a fluorescence which are generated from the bacteria present in the measurement sample irradiated with light from the light source; a light source for irradiating light on a measurement sample prepared from a specimen and a reagent; and a light receiving unit for receiving a scattered light and a fluorescence which are generated from the bacteria present in the measurement sample irradiated with light from the light source; a control unit configured to read out measurement data, wherein the control unit is configured to generate a two-dimensional scattergram on which the measurement data are plotted based on the scattered light and the fluorescence; wherein the control unit is configured for: (a) counting a number of bacteria contained in a plurality of regions (D0,..., D3) on the scattergram, the plurality of regions (D0,..., D3) being regions divided at radially equal angle with an origin of the scattergram as a center; (b) generating frequency distribution data for generating a frequency distribution graph which has as parameters the number of bacteria and distribution position of bacteria in each region of the plurality of regions (D0,...,D3), wherein the distribution position of bacteria comprises a radial angle of each region from the origin of the scattergram; and (c) determining a form of the bacteria contained in the measurement sample based on a region in which the number of bacteria is a peak of the frequency distribution data, wherein the form of the bacteria and the radial angle of each region are assigned based on experimental data. (a) counting a number of bacteria contained in a plurality of regions (D0,..., D3) on the scattergram, the plurality of regions (D0,..., D3) being regions divided at radially equal angle with an origin of the scattergram as a center; (b) generating frequency distribution data for generating a frequency distribution graph which has as parameters the number of bacteria and distribution position of bacteria in each region of the plurality of regions (D0,...,D3), wherein the distribution position of bacteria comprises a radial angle of each region from the origin of the scattergram; and (c) determining a form of the bacteria contained in the measurement sample based on a region in which the number of bacteria is a peak of the frequency distribution data, wherein the form of the bacteria and the radial angle of each region are assigned based on experimental data.