An antenna structure (1) comprising a dielectric base (6) arranged in a non-ground region (Zp) of a substrate (3), and a feeding radiation electrode (7) provided on the dielectric base (6) wherein the outward side face along the edge on one side of the substrate (3) in the dielectric base (6) becomes the side face (6a) on the top side, and a feeding electrode (10) is provided along the side face of the dielectric base (6) in the non-ground region (Zp) of the substrate (3) or on the outside of the substrate (3). One end side of the feeding radiation electrode (7) becomes the feeding end Q side connected with the feeding electrode (10), and the other end side of the feeding radiation electrode (7) becomes the open end K. In the feeding radiation electrode (7), a current path from the feeding end Q side to the open end K has a loop mode extending at least from the top side side face (6a) to the upper surface (6b) of the dielectric base (6). The feeding radiation electrode portion formed on the top side side face (6b) of the dielectric base (6) forms a capacitance for enhancing antenna characteristics in conjunction with the feeding electrode (10).