  We report the results of spectroscopic and photometric observations of the
emission-line object AS 386. For the first time, we found that it exhibits the
B[e] phenomenon and fits the definition of an FS CMa type object. The optical
spectrum shows the presence of a B-type star with the following properties: T_
eff = 11000+/-500 K, log L/L_sun = 3.7+/-0.3, a mass of 7+/-1 M_sun, and a
distance D = 2.4+/-0.3 kpc from the Sun. We detected regular radial velocity
variations of both absorption and emission lines with the following orbital
parameters: P_orb = 131.27+/-0.09 days, semi-amplitude K_1 = 51.7+/-3.0 km/s,
systemic radial velocity gamma = -31.8+/-2.6 km/s, and a mass function of f(m)
= 1.9+/-0.3 M_sun. AS 386 exhibits irregular variations of the optical
brightness (V=10.92+/-0.05 mag), while the near-IR brightness varies up to ~0.3
mag following the spectroscopic period. We explain this behavior by a variable
illumination of the dusty disk inner rim by the B-type component. Doppler
tomography based on the orbital variations of emission-line profiles shows that
the material is distributed near the B-type component and in a circumbinary
disk. We conclude that the system has undergone a strong mass transfer that
created the circumstellar material and increased the B-type component mass. The
absence of any traces of a secondary component, whose mass should be >= 7
M_sun, suggests that it is most likely a black hole.
