To provide a knockdown cooking stove which is easily assembled and disassembled, is compact in size and convenient to carrying, is hardly thermally deformed and excellent in durability.

A cooking stove 1 has a combustion chamber which comprises a table box 20 as a base, an outer frame body 30 constituted thereon and an ash receiving plate 40 arranged in the outer frame body 30. The table box 20 has lateral slits 22 on a pair of opposite height parts 21, and a pair of opposite outer plates 31 of the outer frame body 30 include insertion tabs 34 having hemming parts 34a and supporting holes 35 which support the ash receiving plate 40. The ash receiving plate 40 has hook-type supporting claws 42 at a pair of opposite edges. When upper ends of the pair of outer plates 31 on the table box 20 are lifted while each hook-type supporting claw 42 is inserted into each support hole 35, an insertion tab 34 is fit into the lateral slit 22, the tip of the hemming part 34a is abutted on an outer surface of the table box 20, an outer plate 31 is made to be self-sustained in an erection state, and therefore, the subsequent assembling of a cooking stove is facilitated.