Method of quartz crystal oscillator of odor sensors is drawing public attention recently. In this paper, we modulated gas flow used a magnetic valve in order to improve the rate of discrimination. Furthermore, we change into urethane resin the Film applied to a quartz crystal oscillator, and also report the result which used and discriminated the triangular wave in gas flow modulation. We tried discrimination of five herb species (Linden, Chamomile, Rose hips, Lavender and Lemon balm) using the BP (Back Propagation) method and SOM (Self-Organizing Map). The BP method must use the neural network of three hierarchy, in order to discriminate five herb species. However, this method is complicated. Then, the improvement of discrimination method was done by using SOM, which is simple one, compared with the BP method. The obtained discrimination result is 96.7% and the complexity of discernment has improved.