A cell analyzer comprising: a light source unit configured to apply light to test cells, wherein the test cells contain first substances which are bound to first fluorescent dyes and which serve as an index for therapeutic strategy judgement; an image capturing unit configured to capture an image of fluorescence caused by the applied light; a processing unit configured to process the image obtained by the image capturing unit; and a display unit configured to display a process result obtained by the processing unit, wherein the processing unit is configured to perform the following steps: obtain a first image by performing an inactivation process of quenching, by light irradiation, the first fluorescent dyes, an activation process of activating, by light irradiation, a part of the first fluorescent dyes that have been quenched, and an image capturing process of capturing, by the image capturing unit, an image of the fluorescence by applying light from the light source unit to the test cells; repeating the inactivation process, activation process, and image capturing process a plurality of times; extract bright points based on the first fluorescent dyes on the basis of the first image; classify the extracted bright points into groups each corresponding to one first substance, thereby to obtain the number of the first substances in the test cell on the basis of the number of the classified groups; obtain therapy index information serving as an index for therapeutic strategy judgement, on the basis of the obtained number of the first substances; and cause the display unit to display the obtained therapy index information. a light source unit configured to apply light to test cells, wherein the test cells contain first substances which are bound to first fluorescent dyes and which serve as an index for therapeutic strategy judgement; an image capturing unit configured to capture an image of fluorescence caused by the applied light; a processing unit configured to process the image obtained by the image capturing unit; and a display unit configured to display a process result obtained by the processing unit, wherein the processing unit is configured to perform the following steps: obtain a first image by performing an inactivation process of quenching, by light irradiation, the first fluorescent dyes, an activation process of activating, by light irradiation, a part of the first fluorescent dyes that have been quenched, and an image capturing process of capturing, by the image capturing unit, an image of the fluorescence by applying light from the light source unit to the test cells; repeating the inactivation process, activation process, and image capturing process a plurality of times; extract bright points based on the first fluorescent dyes on the basis of the first image; classify the extracted bright points into groups each corresponding to one first substance, thereby to obtain the number of the first substances in the test cell on the basis of the number of the classified groups; obtain therapy index information serving as an index for therapeutic strategy judgement, on the basis of the obtained number of the first substances; and cause the display unit to display the obtained therapy index information. obtain a first image by performing an inactivation process of quenching, by light irradiation, the first fluorescent dyes, an activation process of activating, by light irradiation, a part of the first fluorescent dyes that have been quenched, and an image capturing process of capturing, by the image capturing unit, an image of the fluorescence by applying light from the light source unit to the test cells; repeating the inactivation process, activation process, and image capturing process a plurality of times; an inactivation process of quenching, by light irradiation, the first fluorescent dyes, an activation process of activating, by light irradiation, a part of the first fluorescent dyes that have been quenched, and an image capturing process of capturing, by the image capturing unit, an image of the fluorescence by applying light from the light source unit to the test cells; repeating the inactivation process, activation process, and image capturing process a plurality of times; extract bright points based on the first fluorescent dyes on the basis of the first image; classify the extracted bright points into groups each corresponding to one first substance, thereby to obtain the number of the first substances in the test cell on the basis of the number of the classified groups; obtain therapy index information serving as an index for therapeutic strategy judgement, on the basis of the obtained number of the first substances; and cause the display unit to display the obtained therapy index information.