A opening control apparatus for a sliding door of a vehicle, includes a driving source, a clutch arranged to connect the driving source and the sliding door in an engaged state and to disconnect the driving source and the sliding door in a disengaged state, and a control section. The control section brings the clutch from the disengaged state to the engaged state when a measured distance of movement of the sliding door from a stop position to a position in one of an opening direction and a closing direction reaches a first predetermined distance and then a measured distance of movement of the sliding door from the position in the one of the opening and closing directions reaches a second predetermined distance, and drives the sliding door to move in the one of the opening and closing directions by the driving source.