Alf Goransson told financial daily Dagens Industri that the firm had taken on 800 extra staff in France and 300 more in Belgium since last week's attacks.
"We have in principle mobilised all the security staff we have available in the Paris region -- but we are looking at seeing if we can take some from other regions in France," said Goransson.
He added the group had "some 20,000 staff" in France, having brought in "800 over the past few days which are really important reinforcements."
The group is also looking to expand numbers in Sweden, which yesterday raised its terrorist threat status to the second-highest level.
"We have taken on 210 people through September and October and expect to find another 500 next year to respond to demand," Goransson said regarding Swedish recruitment.
Securitas, whose share price has risen by close to 10 per cent this week by Thursday morning, recently estimated its sales of technology based-surveillance services will rise this year by 28 per cent.