An apparatus for adjusting direction of air flow of a slim type air vent for an automotive vehicle may include a nozzle type wing that can rotate angularly upwards or downwards and be mounted inside the air vent having slim structure and a gear for rotating the nozzle type wing upwards or downwards is formed on a single transverse wing exposed to the outside such that manipulation force for rotating the single transverse wing angularly upwards or downwards can be transmitted to the nozzle type wing through the gear to rotate the nozzle type wing angularly upwards or downwards and hence the upward or downward direction of air flow being discharged into a cabin can be easily adjusted by upward or downward angular and rotational operation of the nozzle type wing.