Witnesses who have seen the unidentified 25-year-old say he sports a Hitler mustache, combs his hair in the style of the Führer and dresses in Nazi-era regalia.
Police spokesman David Furtner said Monday the suspect was detained after being seen repeatedly in front of the house where Hitler was born in the town of Braunau, on Austria's border with Germany.
Furtner says the man "appears to glorify ... Hitler."
The house itself is the object of a legal squabble between its owner and the government, which wants to take possession and remodel it to erase all associations with Hitler.
Austria's parliament voted in December to buy the three-storey house where Hitler was born, which the government has rented since 1972 to control how it is used.