  We present the results of a survey for emission-line objects based on optical
intermediate-band ($\lambda_{\rm c}$ = 5736 \AA ~ and $\Delta\lambda$ = 280
\AA) and broad-band ($B$, $V$, $R$, and $i^\prime$) observations of the
Subaru/XMM-Newton Deep Field on the 8.2 m Subaru telescope with the Subaru
Prime Focus Camera, Suprime-Cam. All the data were obtained during the
guaranteed time observations of the Suprime-Cam instrument. The
intermediate-band image covered a sky area with 10\minpoint62 $\times
12\minpoint40 \approx 132$ arcmin$^2$ in the Subaru/XMM-Newton Deep Field
(Ouchi et al.).
  Using this image, we have found 23 emission-line sources whose observed
emission-line equivalent widths are greater than 250 \AA. Their optical
multicolor properties indicate that six emission-line sources are Ly$\alpha$
emitters at $z \approx$ 3.7 ($\Delta z \approx 0.22$). They are either intense
starburst galaxies or active galactic nuclei like quasars at $z \approx$ 3.7.
Two more emission-line sources may also be Ly$\alpha$ emitters at $z \approx$
3.7 although their multicolor properties are marginal. Among the remaining 15
emission-line objects, eight objects appear strong emission-line galaxies at
lower redshift; e.g., [O {\sc ii}] $\lambda$3727 emitters at $z \approx 0.54$,
H$\beta$ at $z \approx 0.18$, or [O {\sc iii}]$\lambda$5007 emitters at $z
\approx 0.15$. The remaining seven objects are unclassified because they are
too faint to be detected in broad-band images. We discuss observational
properties of these strong emission-line sources. In particular, our data allow
us to estimate the star formation density at $z \approx 3.7$ for the first
time.
