The bean bug, Riptortus pedestris (Hemiptera: Alydidae), is a major pest of soybean and tree fruit in Korea. To protect crops, chemical insecticides have been widely used. However, the effects of insecticides is not only reduce the pest population but also change of pest behavior. In this study, we tested the effects of two insecticides, etofenprox (pyrethroid) and acetamiprid (neonicotinoid), on the behavior of R. pedestris. Two insecticides were diluted with water based on the conventional spray dose. After exposed to insecticide residue, adult R. pedestris was put individually into a clean petri dish with soybean. The behavior of R. pedestris was video-recorded for 16 hours. The frequencies of approaching to food and feeding were compared to the untreated control group. R. pedestris exposed to etofenprox made more frequent approaching to the food, but those exposed to acetamiprid made less frequent approaching compared to the control group. When compared to the control group, the feeding frequency of acetamiprid-exposed group was significantly reduced but etofenprox-exposed group showed more frequent feeding activity. In both treatments, the feeding probability, calculated by feeding frequency divided by approaching frequency, was reduced compared to the control. We conclude that acetamiprid may protect crops by reducing the frequency of R. pedestris to approach and feed on crops.