Food dough spreading device and food dough spreading method

To provide a food dough spreading method for gradually spreading food dough to make it thinner by supplying the food dough between a plurality of spreading rollers in a spreading unit in which the spreading rollers are arranged in a V-shape. By adjusting a distance between a pair of vibration applying members provided between the spreading rollers arranged in a V-shape, a width dimension of the food dough flowing out from the spreading unit (25) is adjusted, and the vibration applying members are reciprocatively vibrated in a longitudinal direction of the spreading rollers at a position where the width dimension is adjusted. The reciprocative vibration of the pair of vibration applying members is vibration in a direction of approaching and separating from each other.