A heating device for heating a workpiece includes a furnace (10) defining a closed space insulated from an exterior by being surrounded by a heat insulator, a heater disposed in the furnace (10) to heat a workpiece, a support element (30) supporting a workpiece in the furnace (10), and a base (40) holding the support element (30). The base (40) includes a columnar portion (43) serving as the mounting portion, and a support element retaining portion (42) horizontally offset from the columnar portion. The base (40) includes a rib (44) which increases the strength against deformation of the base (40) under the load of the workpiece and/or support elements applied through the support element retaining portion, and a post (45).