To provide a stoker type incinerator having fixed fire grates and a plurality of movable fire grates which are movably provided in a cross direction of the incinerator so as to enable reciprocating movement in the longitudinal direction of the incinerator with respect to the fixed fire grates, wherein high-melting clinker and low-melting metal hardly enter between the movable fire grates, and thus there hardly occurs local combustion of refuse and heating destruction of the fire grates, which are caused by clogging of air holes formed between the movable fire grates.

Surfaces 6h, 8h for supporting sliding movement of fixed fire grates 3, which are adjacently arranged in the cross direction of the incinerator, are constructed to have a shape different from each other. Thus, movable fire grates 4, which are adjacently arranged in the cross direction of the incinerator, are relatively displaced along a vertical surface with the reciprocating movement.