Satisfying customers' affective needs is nowadays seen as a key point to designing a successful product. To ensure this, the relations between physical form elements and affective responses regarding the product should be quantified. In this article, a novel systematic approach is proposed to overcome this problem by representing the relation structure with "IF THEN" type fuzzy rules. A neuro-fuzzy method, named as NEuro-Fuzzy CLASSification (NEFCLASS), is used to extract a rule base with the aid of semantic differential scale (SDS), multi-criteria group decision making (MCGDM) and grey relational analysis (GRA). To prove the applicability of the proposed approach, a case study has been conducted on mobile phone design. Results show that the suggested approach is useful to assist designers to create products satisfying affective needs of customers.