A dual clutch transmission may include a first input shaft having a plurality of odd stage driving gears; a second input shaft disposed to have a concentric shaft with the first input shaft and including a plurality of even stage driving gears; an output shaft; a counter shaft disposed parallel to the first input shaft, the second input shaft, and the output shaft to continuously transfer power to the output shaft and including odd stage driven gears engaged with the odd stage driving gears and even stage driven gears engaged with the even stage driving gears; a plurality of synchronous devices; a plurality of shift forks coupled to the plurality of synchronous devices; and one shift rail provided to commonly guide a linear sliding of the plurality of shift forks.

An interlock mechanism includes a shift-and-select shaft a first fork, a second fork, a first inner lever, a second inner lever, an interlock member coaxially arranged around an outer circumference of the shift-and-select shaft while being allowed to rotate together with the shift-and-select shaft in the rotation direction as a unit and not allowed to be displaced in the axial direction, a first engagement portion formed on the first fork, a second engagement portion formed to project from the second fork, a first engaged portion formed to project from the inter lock member and engaged with the first engagement portion while the interlock member is positioned at a second rotation position and a second engaged portion formed on the interlock member and engaged with the second engagement portion while the interlock member is positioned at a first rotation position.