To provide an apparatus and method for gas supply, and an apparatus and method for cement incineration capable of obtaining gas with high heat production of an enough amount for use in a gas application apparatus.

An apparatus for gas supply comprises a gasifying chamber 1 for decomposing a substance a to be processed to produce combustible gas b and chars h, f, a char combustion chamber 2 for combusting the char content h produced in the gasifying chamber 1 to produce combustion gas e, a first gas passage 301 for supplying the combustible gas b produced in the gasifying chamber 1 to a gas application apparatus 201, and a second gas passage 302 for supplying the combustion gas e produced in the char combustion chamber 2 to the gas application apparatus 201 independently from the combustible gas b. Hereby, combustible gas and combustion gas with different compositions and temperatures can be supplied separately to portions of the gas application apparatus suitable for the respective gases.