To assuredly prevent the exhaust of smoke from the pit of a tunnel in which the exhaust of smoke is inhibited or controlled in the road tunnel that a centralized exhaust type ventilation is carried out by forming an exhaust duct halfway the tunnel.

A wind direction and air velocity and the concentration of smoke are respectively monitored in sections A and B at both the tunnel pits 3a and 3b of the road tunnel 1. The operations of ventilators 5a and 5b of the sections A and B are controlled in accordance with the wind directions, the air velocities and the smoke concentrations of the sections A and B. At least when both the wind directions of the sections A and B are opposite to the wind pressures of the ventilators, the operations of the ventilators 5a and 5b of the sections A and B are controlled so that the wind pressures of the ventilators unconditionally increase.