Hourcade, who has just steered Argentina's second-string Jaguars to a fourth successive Americas Rugby championship title in Canada, replaces Santiago Phelan who quit on Monday after six years in charge.
The Pumas open their European tour with a demanding test against England at Twickenham on November 9. They play Wales and Italy on the following two Saturdays.
England will be stronger than when they won a two-test series 2-0 in Argentina in June without their British and Irish Lions.
Phelan said he decided to quit because internal team matters had been leaked with a detrimental effect on the squad and his coaching staff during a tough second season in the southern hemisphere Rugby Championship in which the Pumas lost their six matches.
"What happened isn't the best way to behave within a rugby team where there are values. With a repetition of these situations and having no control over them, my decision has been to step aside," an emotional Phelan told a news conference.
"My feeling is one of pain after many years of work and effort ...I'm convinced I'm being faithful to my principles."
Former captain Agustin Pichot, now a UAR director, said: "(Phelan) was incredibly dedicated, he learnt as he went along after taking over the team when many (leading) players were retiring after finishing third at the (2007) World Cup.
"I take my hat off to 'Tati'. You can win or lose but you don't find guys like him often. Argentine rugby and the UAR will miss him."
Phelan's assistants Mauricio Reggiardo, Martin Gaitan and Fabian Turnes all handed in their resignations although one or more of them could be retained in the coaching staff that will be under Hourcade, who was not present at the news conference.
Hourcade has played a big part in grooming future Pumas as coach of the Pampas who played for several seasons in South Africa's third tier Vodacom Cup competition, winning it in 2011, and the Jaguars.
Phelan, a former Pumas flanker and veteran of the 1999 and 2003 World Cups, took charge when Marcelo Loffreda quit after steering Argentina to third place at the 2007 tournament in France.
He led Argentina into the quarter-finals of the 2011 World Cup in New Zealand but otherwise had a tough time retaining the high standard the Pumas had reached under the captaincy of former scrumhalf Pichot.
Phelan's record in 45 matches as coach included 13 wins, 31 defeats and a draw against South Africa in last year's debut Rugby Championship.
(Editing by Greg Stutchbury)
