  We present the results of our wide-field narrow band imaging of the field
around the radio galaxy 53W002 at z = 2.390 with Subaru/Suprime-Cam. A custom
made filter NB413 centered at 4140 \AA\ with the width of 83 \AA\ is used to
observe the 31' x 24' area around the radio galaxy. We detected 204 Ly\alpha
emitters (LAEs) at z = 2.4 with a rest frame equivalent width larger than 25
\AA\ to the depth of 26 AB mag (in NB413). The entire LAE population in the
53W002 field has an average number density and distributions of equivalent
width and size that are similar to those of other fields at z ~ 2. We identify
a significant high density region (53W002F-HDR) that spreads over ~ 5' x 4'
near 53W002 where the LAE number density is nearly four times as large as the
average of the entire field. Using the probability distribution function of
density fluctuation, we evaluate the rareness probability of the 53W002F-HDR to
be 0.9^{+2.4}_{-0.62}%, which corresponds to a moderately rich structure. No
notable environmental dependency at the comoving scale of 10 Mpc is found for
the distributions of the Ly\alpha equivalent width and luminosity in the field.
We also detected 4 Ly\alpha blobs (LABs), one of which is newly discovered.
They are all found to be located in the rims of high density regions. The
biased location and unique morphologies in Ly\alpha suggest that galaxy
interaction play a key role in their formation.
