Upgrading method for low-grade coal, and process for production of coke

An upgrading method for converting a low-grade coal having a low rank of coalification into an equivalent of caking coal, characterized by comprising at least a modification step of heating a powdery low-grade coal having a low rank of coalification to a temperature of 350 to 450°C in the presence of a petroleum- or coal-based modifier to modify the low-grade coal, said low-grade coal being a coal having a reactive maceral content exceeding 50% as determined by coal maceral analysis. Thus provided is an upgrading method for converting a non-caking or slightly caking coal, which is classified as low-grade coal, into an equivalent of caking coal which can be used as a material in producing coke for iron-making or the like.