A sample measuring apparatus of an embodiment includes: a laser diode that applies laser light to a measurement specimen prepared from a sample; a detection unit that acquires optical information from a particle in the measurement specimen to which the laser light is applied; a drive circuit that supplies a direct-current drive signal to the laser diode; and a high-frequency conversion circuit that generates a potential that switches between a high level and a low level in a predetermined cycle to guide the drive signal outputted from the drive circuit to a second signal path which is different from a first signal path connected to the laser diode in the predetermined cycle, thereby converting the drive signal to be supplied to the laser diode into a high-frequency signal.