Background: Heart rate variability (HRV) refers to the variation in time interval between heart rates (RR-interval). Studies have demonstrated that emotional disorder is associated with lower HRV. Electrocardiography (ECG) is the conventional HRV measurement conducted by healthcare professionals. Wearable devices with HRV measurement function may be a convenient and low-cost alternative. This study aimed to evaluate the HRV results between a wearable device and ECG. Methods: Parents from disadvantaged families were recruited and requested to wear the wearable device, second generation of Microsoft Band (MS band), on their non-dominant hand and a 7-lead ECG simultaneously for 10 minutes. Mean RR-interval was used to measure the level of HRV; subject with mean RR-interval greater than 750ms was defined as normal. Sensitivity and specificity was used to quantify the consistence between the MS band and the ECG. Results: A total of 40 subjects were recruited. The mean RR-interval of ECG measurements ranged from 487.87 to 1076.5; 9 of them had abnormal RR-interval. The sensitivity and specificity of the MS band were 88.89% and 77.42% respectively. Conclusion: This study showed that wearable device was a reliable instrument for HRV measurement in static posture. Further investigations should look into the accuracy during motion.