A coffee bean roasting machine includes a roast chamber for accommodating coffee beans, a hot blast device for supplying hot or cool air to the roast chamber, and a collection chamber for collecting the outer skins of coffee beans. The collection chamber is in communication with the roast chamber and the bottom of the roast chamber includes a first bean outlet where a chamber door is set for open and close. Coffee beans can be easily taken out from the coffee bean roasting machine, without lifting up the whole roasting machine and tipping it over.