To provide a roll driver of a vertical rolling mill which has short equipment length and low equipment cost, the roll clearance of which can easily be adjusted and which realizes an extensive adjustment range.

The roll driver of the vertical rolling mill is provided with: a vertical rolling machine 25 which is disposed vertically on an upper portion of a housing 23 and has a pair of rolls 26 and 26' which are facing each other and movable in the horizontal direction; a drive shaft 41 which is disposed horizontally below the vertical rolling machine along the moving direction of the roll; and a bevel gear box 42 which is movably disposed according to the movement of the roll 26 between the drive shaft and the rotary shaft 27 of at least one roll of the vertical rolling machine to transmit the driving force of the drive shaft to the rolls.