Abstract: A speed adjusting device for a drill press includes a first variable pulley mounted to the motor shaft and a second variable pulley mounted to the output shaft with a belt connected between the two variable pulleys. A pressing member is mounted to the second variable pulley and the first end of the pressing member is pivotally connected to a fixed member and the second end of the pressing member is connected to a control device. The control device has a connecting member connected to the second end of the pressing member so that the pressing member exerts a force to the second variable pulley by operating the control device to adjust the effective diameter of the belt in the first and the second variable pulley.