To provide a heat treatment apparatus, along with a heat treatment method, capable of improving the accuracy of the analysis of inner atmosphere collected through a sampling pipe from the inside of a heating chamber.

The heat treatment apparatus includes the sampling pipe 15 that is arranged such that the collection side end 15a thereof, which is the side to collect the inner atmosphere of the heating chamber, comes near a heat insulating portion 12. The heat treatment apparatus is configured to: collect the inner atmosphere from the heating chamber 11 through the sampling pipe 15; measure the inner atmosphere collected through the sampling pipe 15, by an atmosphere temperature analyzer provided in an atmosphere control section 13; heat the heating chamber 11 by heaters 21, 21 and control the atmospheric concentration inside the heating chamber 11 by the atmosphere control section 13 based on the measured inner atmosphere data; and then heat-treat a workpiece W accommodated in the heating chamber 11.