A university friend of Akio's and Yoshino's and Yusuke's girlfriend. She has a good relationship with her boyfriend and when he was struggling with hunting for a job, she helped him by cooking his meals, offering guidance on his thesis and helping him out with the job application paperwork. Her own job hunting is also successful, and Yoshino is envious of her and Yusuke's relationship and the fact that they're bettering each other. Naoko started dating Yusuke during their third year at university and continues seeing him after graduation, letting him spend half the week at her apartment.