A wireless device comprising: a frequency converter; a signal processor which outputs a transmission signal (Tx) to the frequency converter; a local oscillator which outputs a local oscillation signal to the frequency converter; an antenna which wirelessly transmits the transmission signal (Tx) that has been up-converted by the frequency converter and filtered; and a filter circuit which is disposed between the frequency converter and the antenna and suppresses the local oscillation signal included in a signal output from the frequency converter, wherein the frequency converter up-converts the transmission signal (Tx) in an intermediate frequency band generated by the signal processor into a signal in a wireless frequency band as an upper side band of the local oscillation signal using the local oscillation signal, wherein when a width of a frequency band of the transmission signal (Tx) is CHwid, a center value of the frequency band of the transmission signal (Tx) is IFtx, a center value of a passband width IFwid of the intermediate frequency band is IFcent, the passband width IFwid being the width of the intermediate frequency band that can be input and output through the signal processor, a lower limit value of a transmittable wireless frequency band specified by specifications of the wireless device is PMlow, and an upper limit value of the transmittable wireless frequency band specified by the specifications of the wireless device is PMhigh, characterized in that in a case where a center value RFtx of the frequency band of the transmission signal after being up-converted and filtered satisfies PMhigh-1/2×IFwid ≤ RFtx ≤ PMhigh-1/2×CHwid, a frequency ω LO of the local oscillation signal satisfies ω LO = PMhigh − 1/2 × IFwid − IFcent and IFtx = RFtx − ω LO. a frequency converter; a signal processor which outputs a transmission signal (Tx) to the frequency converter; a local oscillator which outputs a local oscillation signal to the frequency converter; an antenna which wirelessly transmits the transmission signal (Tx) that has been up-converted by the frequency converter and filtered; and a filter circuit which is disposed between the frequency converter and the antenna and suppresses the local oscillation signal included in a signal output from the frequency converter, wherein when a width of a frequency band of the transmission signal (Tx) is CHwid, a center value of the frequency band of the transmission signal (Tx) is IFtx, a center value of a passband width IFwid of the intermediate frequency band is IFcent, the passband width IFwid being the width of the intermediate frequency band that can be input and output through the signal processor, a lower limit value of a transmittable wireless frequency band specified by specifications of the wireless device is PMlow, and an upper limit value of the transmittable wireless frequency band specified by the specifications of the wireless device is PMhigh, characterized in that in a case where a center value RFtx of the frequency band of the transmission signal after being up-converted and filtered satisfies PMhigh-1/2×IFwid ≤ RFtx ≤ PMhigh-1/2×CHwid, a frequency ω LO of the local oscillation signal satisfies ω LO = PMhigh − 1/2 × IFwid − IFcent and IFtx = RFtx − ω LO.