According to one embodiment, an antenna apparatus includes an antenna element and a parasitic element. The antenna element includes an element main body whose first end portion is connected to a feed point and second end portion as the other end portion is open, with the element main body being configured to be selectable between a first state in which the element main body is retracted into a housing of the electronic device and a second state in which the element main body extends from the housing. The parasitic element is disposed such that when the antenna element is in the first state, the first end portion is connected to the element main body of the antenna element and the second end portion is connected to a ground portion.