To provide a carriage type heating furnace capable of surely sealing a specific space (clearance) between a hearth member and a carriage base part with a simple mechanism.

This carriage type heating furnace 1 comprises a sealing means 6 provided with a seal member having a contact face of which a lower face is substantially flush with an opposite end part of the base part, at an end part of the hearth member 4 faced to the base part 5 of the carriage, and sealing the specific space (clearance) a by being kept into contract with lower faces of both end parts of the hearth member and the carriage base part, a supporting means vertically movably supporting the seal member, a pressing spring 8 for pressing the seal member to raise the same, and an opening and closing means for raising the seal member by the energizing force of the pressing spring to seal the specific space, and lowering the seal member against the energizing force of the pressing spring to open the specific space.