A wireless device, including an antenna different from another antenna included in one of two casings, in a joint part where the two casings are joined together, is capable of reducing deterioration in properties of the antenna included in the joint part. The wireless device (1) of the present invention includes: an upper casing (10), housing a casing antenna (11) that resonates with a first frequency; a lower casing (20), housing a matching circuit (23) of the casing antenna (11); a hinge part (31), joining the upper casing (10) with the lower casing (20), including a built-in antenna (32) that resonates with a second frequency different from the first frequency, and including feeding sections (33) and (34) for coupling the matching circuit (23) to the casing antenna (11); and transmission elements (12) and (22), being disposed on at least any one of a signal path that connects the casing antenna (11) and the feeding section (33) and a signal path that connects the matching circuit (23) and the feeding section (34), the transmission elements (12) and (22) (i) giving passage to a signal having the first frequency and (ii) blocking a signal having the second frequency.