Here is disclosed a controller for operation of transmission in motor car comprising a control cable (14) of triple structure consisting of an outer tube (15), an inner tube (16) slidably inserted into the outer tube (15) and a length of wire (17) slidably inserted into the inner tube (16), characterized by that any one end of the outer tube (15) is fixed to a car body, one end of any one of the inner tube (16) and the wire (17) is engaged with a SELECT mode operating mechanism provided adjacent a control lever (6) while one end of the other one of the inner tube (16) and the wire (17) is engaged with a SHIFT mode operating mechanism also provided adjacent the control lever (6), the other end of the outer tube (15) is fixed to a transmission casing, the other end of any one of the inner tube (16) and the wire (17) is engaged with a SELECT mode operating mechanism provided adjacent a transmission unit while the other end of the other one of the inner tube (16) and the wire (17) is engaged with a SHIFT mode operating mechanism provided adjacent the transmission unit.