We present the results of the spectropolarimetric study of the classical Cepheid \eta Aql in 2002 , 2004 , 2010 , and 2012 .
The longitudinal magnetic field of \eta Aql was found to be variable with the pulsation cycle of 7.176726 day .
The amplitude , phase , and mean value of the field vary from year to year presumably due to stellar rotation or dynamo mechanisms .