A method of forming a rolled food dough from a food dough piece comprising steps of: conveying a food dough piece into a space between a middle-speed conveyor and a high-speed conveyor, a speed of the high-speed conveyor being higher than a speed of the middle-speed conveyor, the high-speed conveyor facing the middle-speed conveyor and moving in the same direction as the middle-speed conveyor; feeding a high-speed-conveyor-side portion of the food dough piece faster than a middle-speed-conveyor-side portion of the food dough piece due to a speed difference between the middle-speed conveyor and the high-speed conveyor, so as to deflect a downstream end portion of the food dough piece toward a middle-speed-conveyor side; causing the deflected downstream end portion of the food dough piece to collide with an upstream end portion of a low-speed conveyor which is disposed downstream of the middle-speed conveyor, a speed of which is lower than the middle-speed conveyor, and which moves in the same direction as the middle-speed conveyor; forming a buckling part in the deflected downstream end portion of the food dough due to a speed difference between the middle-speed conveyor and the low-speed conveyor, and folding the deflected downstream end portion at the buckling part; adhesively pressing the folded downstream end portion of the food dough piece between the low-speed conveyor and the high-speed conveyor facing the low-speed conveyor so as to form a rolling core; and rolling the food dough piece around the rolling core between the low-speed conveyor and the high-speed conveyor due to a speed difference between the low-speed conveyor and the high-speed conveyor so as to form a rolled food dough. conveying a food dough piece into a space between a middle-speed conveyor and a high-speed conveyor, a speed of the high-speed conveyor being higher than a speed of the middle-speed conveyor, the high-speed conveyor facing the middle-speed conveyor and moving in the same direction as the middle-speed conveyor; feeding a high-speed-conveyor-side portion of the food dough piece faster than a middle-speed-conveyor-side portion of the food dough piece due to a speed difference between the middle-speed conveyor and the high-speed conveyor, so as to deflect a downstream end portion of the food dough piece toward a middle-speed-conveyor side; causing the deflected downstream end portion of the food dough piece to collide with an upstream end portion of a low-speed conveyor which is disposed downstream of the middle-speed conveyor, a speed of which is lower than the middle-speed conveyor, and which moves in the same direction as the middle-speed conveyor; forming a buckling part in the deflected downstream end portion of the food dough due to a speed difference between the middle-speed conveyor and the low-speed conveyor, and folding the deflected downstream end portion at the buckling part; adhesively pressing the folded downstream end portion of the food dough piece between the low-speed conveyor and the high-speed conveyor facing the low-speed conveyor so as to form a rolling core; and rolling the food dough piece around the rolling core between the low-speed conveyor and the high-speed conveyor due to a speed difference between the low-speed conveyor and the high-speed conveyor so as to form a rolled food dough.