The accident occurred near the Caltex petrol station at about 8:30am.
The pickup was carrying about nine Myanmar workers in the back when the driver lost control of the vehicle and struck the sign, explained Lt Pongpipad Khamchompu of the Thalang Police.
All the workers in the pickup suffered injuries, Lt Pongpipad added.
An ambulance from Thalang Hospital and a rescue team from Srisoonthorn Municipality soon arrived at the scene.
One of the workers who suffered severe injuries was rushed to Thalang Hospital. Emergency responders administered CPR en route, but the man was pronounced dead on arrival, Lt Pongpipad confirmed.
Police have yet to release the names of the man who died and his fellow coworkers injured in the accident.
The name of the driver of the pickup also has yet to be released.
Police are continuing their investigation into the accident.
Under new road safety regulations issued by the Royal Thai Police that came into effect on Saturday (Feb 17), passengers riding in the back of pickup trucks are not required to use any form of seatbelt restraint, but the driver must not exceed 60km/h.