This isn't true. It's a common misconception.

I read a scholarly article by Allen Gindler a few months back tracing the history of modern fascism. People often point to Hitler as an example of "right-wing fascism," but technically Hitler's politics were left of center. Here is a quote from his conclusions:

"The truth is that fascism and National Socialism have always been non-Marxian flavors of socialism and should occupy the right wing of the Left on the political spectrum. Their placement on the extreme right wing is artificial, unwarranted, and was done as a purely propagandistic measure during the acute internecine struggle among socialist currents."

I can't give you the link to the article because it automatically takes you to the pdf; but the title is "How and Why Fascism and Nazism Became the 'Right'". You should be able to find it fairly easily.