PURPOSE: Grinding machines which are installed on an elevating work platform or an aerial lift is provided to secure safety and to reduce operating time for grinding a surface of an object. CONSTITUTION: Grinding machines comprise a fixing unit(100) which detachably fixed on an object and a horizontal supporting unit(200). The horizontal supporting unit comprises: a grinder(300) which is installed on the end part(201) and grinds a surface of an object; and a handle(400) which is installed on the back end part(202) and controls a vertical motion of the horizontal supporting unit by an operator. The grinder and a steering wheel move with seesaw-motion to the top and the bottom on the upper part of the fixing unit.
