Provided is a vehicle speed control device with respect to which the speed at which a centrifugal brake operates can be easily changed from the outside without disassembling the device. A brake drum 11 is fixed to a vehicle body 101a. A brake shoe 23 rotates around a rotary shaft 20 of the wheel 101c, and reduces the rotation speed of the wheel 101c as a result of coming into contact with an inner circumferential side face of the brake drum 11. A spring 24 prevents contact between the brake drum 11 and the brake shoe 23 when the rotation speed of the wheel 101c is lower than or equal to a predetermined speed, and permits contact between the brake drum 11 and the brake shoe 23 when the rotation speed of the wheel 101c exceeds the predetermined speed. A position change mechanism 25 is installed within the brake drum 11, and changes the position of an end of the spring 24 on one end side. A transmission mechanism 26 transmits a force that is input by an external operation to the position change mechanism 25 and drives the position change mechanism.