A solid fuel manufacturing apparatus (10; 110; 210; 310) including: mixture producing means (10A; 210A; 310A) configured to produce a mixture by kneading combustible waste containing moisture and a dehydrating agent acting to accelerate removal of the moisture from the combustible waste,; rotary drum (30; 130; 230) configured to be cylindrical and rotatable and contain the mixture in an internal space (30S; 230S); intake means configured to introduce outside air into the rotary drum (30; 130; 230); exhaust means (41; 241) configured to discharge exhaust air out of the rotary drum (30; 130; 230); drive means (51; 151; 251) configured to rotate the rotary drum (30; 130; 230); drum lower side supporting parts (56; 256) in four places, each provided with a load sensor (59; 259), the load sensors (56; 256) being provided and configured to detect a load that acts on a predetermined portion of each drum lower side supporting part (56; 256); a control board (60; 160; 260) configured to control movement of the drive means; based on a detection signal of each load sensor (59; 259), wherein the control board is capable of reversing the rotation direction of the rotary drum to return the gravity center of the entire drum to an original position and thus controls the rotation of the drum to prevent the mixture from staying in the one-sided position; and breaking means (72; 272) configured to break up the mixture contained in the mixture containing means, wherein the dehydrating agent is a treatment agent made of an emulsion containing synthetic resin; and the breaking means is placed along an inner peripheral wall (31; 231) of the mixture containing means and configured to scoop the mixture upward in the internal space and allow the mixture to freely fall from above in the internal space by rotation of the mixture containing means. mixture producing means (10A; 210A; 310A) configured to produce a mixture by kneading combustible waste containing moisture and a dehydrating agent acting to accelerate removal of the moisture from the combustible waste,; rotary drum (30; 130; 230) configured to be cylindrical and rotatable and contain the mixture in an internal space (30S; 230S); intake means configured to introduce outside air into the rotary drum (30; 130; 230); exhaust means (41; 241) configured to discharge exhaust air out of the rotary drum (30; 130; 230); drive means (51; 151; 251) configured to rotate the rotary drum (30; 130; 230); drum lower side supporting parts (56; 256) in four places, each provided with a load sensor (59; 259), the load sensors (56; 256) being provided and configured to detect a load that acts on a predetermined portion of each drum lower side supporting part (56; 256); a control board (60; 160; 260) configured to control movement of the drive means; based on a detection signal of each load sensor (59; 259), wherein the control board is capable of reversing the rotation direction of the rotary drum to return the gravity center of the entire drum to an original position and thus controls the rotation of the drum to prevent the mixture from staying in the one-sided position; and drum lower side supporting parts (56; 256) in four places, each provided with a load sensor (59; 259), the load sensors (56; 256) being provided and configured to detect a load that acts on a predetermined portion of each drum lower side supporting part (56; 256); a control board (60; 160; 260) configured to control movement of the drive means; based on a detection signal of each load sensor (59; 259), wherein the control board is capable of reversing the rotation direction of the rotary drum to return the gravity center of the entire drum to an original position and thus controls the rotation of the drum to prevent the mixture from staying in the one-sided position; and breaking means (72; 272) configured to break up the mixture contained in the mixture containing means, wherein the dehydrating agent is a treatment agent made of an emulsion containing synthetic resin; and the breaking means is placed along an inner peripheral wall (31; 231) of the mixture containing means and configured to scoop the mixture upward in the internal space and allow the mixture to freely fall from above in the internal space by rotation of the mixture containing means.