The invention provides an eight-speed double clutch speed change device, and belongs to the technical field of transmissions. The speed change device comprises a main input shaft, a first input device, a second input device, a double clutch, a first output device, a second output device, a third output device and a plurality of synchronizers. The first input device comprises a first input shaft and three odd-gear driving gears. The second input device comprises a second input shaft and two even-gear driving gears. The first output device comprises a first output shaft and four driven gears arranged on the first output shaft. One of the three odd-gear driving gears is a common driving gear engaged with two driven gears. Each of the two even-gear driving gears is a common driving gear engaged with two driven gears. One of the four driven gears on the first output shaft serves as a reverse-gear middle idle gear. The speed change device is small in axial length, wide in reverse-gear gear layout and speed ratio range and wide in parking ratchet wheel layout range.