PROBLEM TO BE SOLVED: To provide a support driver capable of efficiently driving a support into ground.SOLUTION: A support driver 1 includes a fixing member 2 that is fixed to an intermediate part of a support S, and a hammer member 3 that is slidably attached to the support S in an upper position of the fixing member 2. An operator P slides the hammer member 3 upward and downward to make an impact on the fixing member 2. Thus, the support S is driven into the ground.