A measuring apparatus includes a flow cell through which a sample containing particles flows, a light source for irradiating light on the sample flowing through the flow cell, a fluorescence detector for detecting the fluorescence generated from the sample irradiated with light from the light source, and a control unit for flowing a positive control sample containing a fluorescent dye through the flow cell, measuring the fluorescence generated from the positive control sample irradiated by the light from the light source via the fluorescence detector, comparing the obtained measurement value and a reference value, and adjusting the detection sensitivity of the fluorescence detector according to the comparison result.