A method for manufacturing a rotation angle detector is provided. An insulator is mounted on a sensor core. A plurality of winding slackening pins are disposed at predetermined positions between a plurality of teeth and a plurality of terminal pins so as to project out of the a first surface side of the insulator. A first and second conductor wire are wound so as to dispose a first and second lead wire portion of each conductor wire wound on the teeth under tension between the teeth and the terminal pin by hooking each wire lead portion onto a winding hooking pin and a winding slackening pin. The winding slackening pins are removed so that the first and second lead wire portions have a predetermined amount of slack.