A heating device for heating a workpiece, comprising: a furnace defining a closed space insulated from exterior and surrounded by a heat insulator, the furnace having a sidewall; a heater disposed in the furnace to heat a workpiece; horizontally spaced support elements for supporting a workpiece in the furnace , each support element comprising a horizontal bar; and horizontally arranged bases each holding two of the support elements , each base comprising: a horizontally planar portion ; a columnar mounting portion extending downward from a part of the planar portion between the support elements , the mounting portion being directly mounted to the sidewall of the furnace or indirectly mounted to the sidewall of the furnace via an intervening structure ; support element retaining portions extending upward from the planar portion , each support element retaining portion holding an end of the respective support element , the support element retaining portion being horizontally offset from the mounting portion ; and at least one rib extending upward or downward from the planar portion to increase the strength of the base against deformation due to a load of the workpiece and/or support element applied through the support element retaining portion . a furnace defining a closed space insulated from exterior and surrounded by a heat insulator, the furnace having a sidewall; a heater disposed in the furnace to heat a workpiece; horizontally spaced support elements for supporting a workpiece in the furnace , each support element comprising a horizontal bar; and horizontally arranged bases each holding two of the support elements , each base comprising: a horizontally planar portion ; a columnar mounting portion extending downward from a part of the planar portion between the support elements , the mounting portion being directly mounted to the sidewall of the furnace or indirectly mounted to the sidewall of the furnace via an intervening structure ; support element retaining portions extending upward from the planar portion , each support element retaining portion holding an end of the respective support element , the support element retaining portion being horizontally offset from the mounting portion ; and at least one rib extending upward or downward from the planar portion to increase the strength of the base against deformation due to a load of the workpiece and/or support element applied through the support element retaining portion . a horizontally planar portion ; a columnar mounting portion extending downward from a part of the planar portion between the support elements , the mounting portion being directly mounted to the sidewall of the furnace or indirectly mounted to the sidewall of the furnace via an intervening structure ; support element retaining portions extending upward from the planar portion , each support element retaining portion holding an end of the respective support element , the support element retaining portion being horizontally offset from the mounting portion ; and at least one rib extending upward or downward from the planar portion to increase the strength of the base against deformation due to a load of the workpiece and/or support element applied through the support element retaining portion . <EOS>