The invention provides a radio device in which multi-resonance promotion and impedance adjustment can be readily performed and a restriction in a mounting space can be dissolved, and an electronic apparatus having the same installed therein. Provision of a stub (123) having a large area and serving as a frequency matching portion as well in a folded monopole antenna (120) results in that a conductor area can be increased, and a resonance frequency can be shifted to lower frequencies. In addition, a frequency of a radio communication antenna can be readily adjusted because the resonance frequency is adjusted by cutting the stub (123).