Despite that 80% of marketers find influencer marketing effective and that 89% ROI (Return on Investment) from influencer marketing is comparable to or better than other marketing channels, the use of Instagram Influencer has not considered as a strategy and tools to improve sales. Only 17% marketers spend over half their budget on influencer marketing, and the majority of marketers spend less than 10% on influencer marketing. The main factors that influenced the actual purchase according to theory of planned behavior (TPB) are intention to purchase, attitude toward purchase, subjective norm, perceived behavioral control.