PURPOSE: To enable energy-saving operation by making a ventilation wind stably flow in a tunnel, reducing a tendency to deterioration in contamination density and eliminating unnecessary operation of a ventilator.

CONSTITUTION: This tunnel ventilation control unit consists of a traffic quantity measuring means 3 which measures the traffic quantity in the tunnel, a mean traffic quantity calculation means 6 which finds a past mean traffic quantity in a specific period from the measured traffic quantity, a minimum operated equipment quantity setting means 7 which outputs the minimum number of operated equipments, a ventilator feedback control means 9 which calculates the number of operated ventilators that measured values of fume transmissivity meters 41 and 42 and an anemometer anemoscope 5 are held nearby target fume transmissivity and a target roadway wind velocity, and a control output determining means 10 which determines a control output that never makes the number of operated ventilators calculated by the control means less than the minimum number of operated ventilators outputted from the minimum operated equipment number setting means; and this tunnel ventilation control unit operates and stops the respective ventilators according to the control output.