Context : Aims : We study the O-type star HD 161853 , which has been noted as a probable double-lined spectroscopic binary system . Methods : We secured high-resolution spectra of HD 161853 during the past nine years . We separated the two components in the system and measured their respective radial velocities for the first time . Results : We confirm that HD 161853 is an \sim 1 Ma old binary system consisting of an O8 V star ( M _ { A,RV } \geq 22 M _ { \odot } ) and a B1–3 V star ( M _ { B,RV } \geq 7.2 M _ { \odot } ) at about 1.3 kpc . From the radial velocity curve , we measure an orbital period P = 2.66765 \pm 0.00001 d and an eccentricity e = 0.121 \pm 0.007 . Its V -band light curve is constant within 0.014 mag and does not display eclipses , from which we impose a maximum orbital inclination i = 54 deg . HD 161853 is probably associated with an H ii region and a poorly investigated very young open cluster . In addition , we detect a compact emission region at 50 arcsec to HD 161853 in 22 \mu m- WISE and 24 \mu m- Spitzer images , which may be identified as a dust wave piled up by the radiation pressure of the massive binary system . Conclusions :