We present results from a 50 ks observation of the narrow-line Seyfert 1 galaxy Ark 564 with the Chandra HETGS .
The spectra above 2 keV are modeled by a power-law with a photon-index of 2.56 \pm 0.06 .
We confirm the presence of the soft excess below about 1.5 keV .
If we fit the excess with blackbody model , the best-fit temperature is 0.124 keV .
Ark 564 has been reported to show a peculiar emission line-like feature at 1 keV in various observations using lower resolution detectors , and the Chandra grating spectroscopy rules out an origin of blends of several narrow emission lines .
We detect an edge-like feature at 0.712 keV in the source rest frame .
The preferred interpretation of this feature is combination of the O vii K-edge and a number of L-absorption lines from slightly ionized iron , which suggests a warm absorber with ionization parameter \xi \sim 1 
and N h ~ { } \sim 10 ^ { 21 } cm ^ { -2 } .
These properties are roughly consistent with those of the UV absorber .
We also detect narrow absorption lines of O vii , O viii , Ne ix , Ne x , and Mg xi 
at the systemic velocity .
From these lines , a second warm absorber having \log \xi \sim 2 and N h ~ { } \sim 10 ^ { 21 } cm ^ { -2 } 
is required .