This study concerns a measurement device and an algorithm of the laryngeal elevation for the Mendelsohn maneuver. The measurement device is band-shaped and measures the change of the circumferential length of the neck by stretchable strain sensors. The device is lightweight of 35 g. The algorithm detects the onset and offset points in time of the laryngeal elevation by the first-order difference and the dynamic time warping distance. Twelve elderly people participated in an experiment to validate the effectiveness of the device. A clustering method separated the measurement data into two groups based on their waveforms. We defined template data from the measurement data. The algorithm detected the onset and offset time by using the template data. Although the offset time of a group had an error of about 4 s, the onset and offset time points of the other group were errors within 1 s.