It brings Guidolin's four-year spell as head coach to an end, with the Friuli club finishing 13th in his final season in charge, after top-five placings in each of his first three at the helm.
In a press conference on Tuesday, the 58-year-old confirmed the decision, and said he was looking forward to life in his new role.
"I'm glad to be here, and give my contribution to this new challenge," he said.
"It's the start of a new adventure and I'm curious about how it goes. It's a new phase of my life.
"I have a little bit of sadness, but I want to emphasise that this is my choice, the best for me.
"I think well of my all my colleagues. There were so many good memories.
"My wife is very happy, especially because we live here. My kids are convinced that it is the right choice."
