To provide a burning device of simple constitution capable of efficiently burning the synthetic solid fuel which is manufactured from the classified refuse and rich in ash without allowing combustion gas and unburnt gas to leak.

In a fixed bed synthetic solid fuel burning device in which the synthetic solid fuel 12 is burned on a hearth 1b, a vibration generator 32 is fitted to a bottom part of a combustion furnace A, and ash deposited on the hearth is moved toward an ash discharge port 20. The ash discharge port 20 is closed by the ash to prevent the combustion gas or the unburnt gas in a combustion chamber S from leaking. Even when the gas has leaked, it is returned to the combustion chamber S by a combustion air blower 50.