An antenna apparatus comprising: a ground portion; a first antenna element; and a second antenna element between the first antenna element and the ground portion; wherein the first antenna element has a first end connected to a feed terminal and a second end kept open; the first antenna element includes a linear portion including the second end; the linear portion of the first antenna element ( is in parallel with the ground portion; an element length from the feed terminal to the second end is set to substantially a quarter of a wavelength corresponding to a preset first resonance frequency; and the second antenna element has a first end connected to a first point of the first antenna element, a second end kept open and a third end kept open; the second antenna element includes a first antenna portion and a second antenna portion; the first antenna portion extends linearly from the first point to the second end of the second antenna element; an element length from the feed terminal to the second end of the second antenna element through the first point is set to substantially a quarter of a wavelength corresponding to a preset second resonance frequency; the second antenna portion bifurcates from the first antenna portion at a second point between the first point and the second end of the second antenna element and extending to the third end of the second antenna element; an element length of the second antenna portion from the feed terminal to the second end of the second antenna element is set to substantially 3/4 of a wavelength corresponding to a preset third resonance frequency; a capacitor element is provided between the feed terminal and the first point; the first antenna portion is parallel with a ground portion and the linear portion of the first antenna element; the second antenna portion includes a first part and a second part; the first part of the second antenna portion extends from the second point perpendicularly to the ground portion, the second part of the second antenna portion extends from the first part of the second antenna portion toward the feed terminal in parallel with the ground portion, the linear portion of the first antenna element and the first antenna portion. a ground portion; a first antenna element; and a second antenna element between the first antenna element and the ground portion; wherein the first antenna element has a first end connected to a feed terminal and a second end kept open; the first antenna element includes a linear portion including the second end; the linear portion of the first antenna element ( is in parallel with the ground portion; an element length from the feed terminal to the second end is set to substantially a quarter of a wavelength corresponding to a preset first resonance frequency; and the second antenna element has a first end connected to a first point of the first antenna element, a second end kept open and a third end kept open; the second antenna element includes a first antenna portion and a second antenna portion; the first antenna portion extends linearly from the first point to the second end of the second antenna element; an element length from the feed terminal to the second end of the second antenna element through the first point is set to substantially a quarter of a wavelength corresponding to a preset second resonance frequency; the second antenna portion bifurcates from the first antenna portion at a second point between the first point and the second end of the second antenna element and extending to the third end of the second antenna element; an element length of the second antenna portion from the feed terminal to the second end of the second antenna element is set to substantially 3/4 of a wavelength corresponding to a preset third resonance frequency; a capacitor element is provided between the feed terminal and the first point; the first antenna portion is parallel with a ground portion and the linear portion of the first antenna element; the second antenna portion includes a first part and a second part; the first part of the second antenna portion extends from the second point perpendicularly to the ground portion, the second part of the second antenna portion extends from the first part of the second antenna portion toward the feed terminal in parallel with the ground portion, the linear portion of the first antenna element and the first antenna portion.