A heart rate measurement device applies a heart rate measurement method for measuring heart rates of a subject. The heart rate measurement device includes a microprocessor, a photoplethysmography sensing module electrically connected with and controlled by the microprocessor, a triaxial accelerometer sensor electrically connected with the microprocessor, and an analog-to-digital converter. The photoplethysmography sensing module senses biological signals of the subject. The triaxial accelerometer sensor senses whether the subject is in a motion status and sends sensing results to the microprocessor. The analog-to-digital converter is electrically connected with the microprocessor and the photoplethysmography sensing module. The analog-to-digital converter converts the biological signals into digital signals and sends the digital signals to the microprocessor.
