  The intermediate mass Herbig Ae star V1787 Ori is a member of the L1641
star-forming region in the Orion A molecular cloud. We report the detection of
an M-type companion to V1787 Ori at a projected separation of 6.66"
(corresponding to 2577 au), from the analysis of VLT/NACO adaptive optics
$K_s$-band image. Using astrometric data from Gaia DR2, we show that V1787 Ori
A and B share similar distance ($d$ $\sim$ 387 pc) and proper motion,
indicating that they are physically associated. We estimate the spectral type
of V1787 Ori B to be M5 $\pm$ 2 from color--spectral type calibration tables
and template matching using SpeX spectral library. By fitting PARSEC models in
the Pan-STARRS color-magnitude diagram, we find that V1787 Ori B has an age of
8.1$^{+1.7}_{-1.5}$ Myr and a mass of 0.39$^{+0.02}_{-0.05}$ $M_\odot$. We show
that V1787 Ori is a pre-main sequence wide binary system with a mass ratio of
0.23. Such a low mass ratio system is rarely identified in Herbig Ae/Be binary
systems. We conclude this work with a discussion on possible mechanisms for the
formation of V1787 Ori wide binary system.
