The present invention provides an ink jet printing apparatus and a method for controlling an ink jet printing apparatus which, during a non-print operation excluding a print operation, can stir ink at a required time and to a required level according to the state of the ink in the ink tank. During a non-print operation excluding a print operation accompanied by a reciprocal movement of the carriage, a stir operation is executed to stir the ink in the ink tank by reciprocating the carriage according to a stir mode. As the stir mode, one of different modes is set according to an elapsed time from the previous stir operation.