To convert thinned wood or ligneous waste material into briquette fuel with a simple method, and effectively utilize thinned wood at low cost.

The briquette fuel is obtained by the following processes where woody chips and sawdust are added to a gel-like gelatinized substance obtained by suspending starch in water and heating, and mixed to form a mixture; and the mixture is molded into an optional shape, and dried. The mixing ratios of the raw materials of the mixture are 1,500 to 2,500 cc of water; 2 to 4 kg of woody chip having 1-10 mm thickness, 5-40 mm width and 10-70 mm length; and 4 to 6 kg of sawdust, respectively per 1 kg of starch powder.