  We report on the weak lensing detection of a filament between two galaxy
clusters at $z=0.55$, CL0015.9+1609 and RX J0018.3+1618. We conduct weak
lensing analysis of deep multi-band Subaru/Suprime-Cam images with $Lensfit$.
The weak lensing signals from the filament are contaminated by signals from the
adjacent massive clusters and we statistically subtract the cluster component
using two different methods. Both methods yield consistent shear profiles on
the filament with $\gtrsim2\sigma$ significance and the average surface mass
density of the filament is $<\Sigma>=(3.20\pm0.10)\times10^{14}h$
M$_\odot$Mpc$^{-2}$, which is in broad agreement with previous studies.
On-going surveys such as Hyper Suprime-Cam will identify more filaments, which
will serve as a new probe of structure formation in the Universe.
