Poor work conditions and excessive physical demands associated with construction tasks increase the risks associated with construction workers' impaired mental and physical health. To prevent detrimental impacts that such risks have on project performance, measuring construction workers' physical and mental status should take precedence. In the same vein, recent advancements in wearable technologies and physiology have opened a new door toward an objective, nonintrusive, and continuous field measurement of workers' physical and mental status using physiological signals acquired from wearable devices. Despite this opportunity, there is a notable paucity of studies investigating the potential of using physiological signals collected from wearable devices to understand workers' physical and mental status. To bridge this gap, this study suggests utilizing an off-the-shelf wristband-type wearable sensor to acquire construction workers' physiological signals as a means of assessing workers' physical and mental state. This study investigates the distinguishing power of three biosignals - electrodermal (EDA), skin temperature (ST), and photoplethysmogram (PPG) - in detecting workers' physical and mental states during their work on the site. The 10 h of biosignals were acquired from two workers in different conditions (e.g., light work, medium work) and tasks (e.g., resting, installing drywall, etc.). Signal processing methods (e.g., filtering methods) were applied to remove the signal artifacts from the biosignals. Electrodermal response (EDR), mean ST values after finite impulse responses filtering, heart rate variability (HRV), inter-beat interval (IBI), and percentage heart rate (%HRR) were calculated as the metrics to investigate the potential of suggested biosignals in measuring workers' physical and mental states. Results indicated a clear difference in EDA values, HRV, and %HRR values while subjects were working in various real work conditions. Results confirm the feasibility of the wristband-type wearable sensor to evaluate construction workers' physical and mental states, which can lead to early detection of the stressor factors in construction sites.