We present here new measurements of the longitudinal magnetic field (Be) in the binary system HD 9996, where the primary companion is an Ap star. Series of 63 Be observations was obtained in years 1994-2011 with the 1-m optical telescope of the Special Astrophysical Observatory (Russia). New magnetic data allowed us to refine the long-term magnetic period of HD 9996 to Pmag=21.8 years. Compilation of archival photometric data showed the existence of long-term variations of HD 9996 in time scale of 22-23 yr consistent with Pmag. We identify Pmag with the precession period of the primary Ap star and summarize search for a short-term rotational period and the rotational line broadening in this star.
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