A cyanate ester compound represented by the formula (1), ##STR00001## wherein Ar.sub.2 represents a phenylene group, a naphthylene group or a biphenylene group, Ar.sub.1 represents a naphthylene group or a biphenylene group when Ar.sub.2 is a phenylene group, or Ar.sub.1 represents a phenylene group, a naphthylene group or a biphenylene group when Ar.sub.2 is a naphthylene group or a biphenylene group, R.sub.x represents all substituents of Ar.sub.1, each R.sub.x is the same or different and represents hydrogen, an alkyl group or an aryl group, Ry represents all substituents of Ar.sub.2, each R.sub.y is the same or different and represents hydrogen, an alkyl group or an aryl group, and n is an integer of 1 to 50.