A measurement apparatus and method for measuring a vital sign of a subject are provided. A plurality of frames showing a subject is captured. A region of interest (ROI) on the subject is detected. A vital-sign signal is generated according to the sensing signals related to the ROI. A quality index of the vital-sign signal is evaluated. Whether the subject is a living body is determined according to the quality index. A determination result of determining whether the subject is the living body is used to control a heart-rate measurement operation.
