The present invention relates to a substrate processing apparatus. The substrate processing apparatus includes a chamber including a chamber body of which one side is opened and having an inner space and a door opening and closing the chamber body, first susceptors disposed to be spaced apart from each other within the chamber, supports each of which is connected to one side surface of the door to support the substrate in parallel to the first susceptor, second susceptors disposed on the supports along a longitudinal direction of the door, the second susceptors being spaced apart from each other in a direction crossing the first susceptors, and at least one heat source unit disposed at least one surface of the chamber to heat the susceptors.