An imaging apparatus includes a photographing optical lens assembly and an image sensor. The photographing optical lens assembly includes a plurality of lens elements. The plurality of lens elements includes, in order from an object side to an image side, a first lens element, a second lens element and a last lens element. Each of the lens elements has an object-side surface facing the object side and an image-side surface facing the image side. At least one of the lens elements is plastic and at least one of the lens elements has at least one inflection point. There is at least one variable axial distance between adjacent lens elements thereof.