  The in-orbit performance and calibration of the Hard X-ray Detector (HXD) on
board the X-ray astronomy satellite Suzaku are described. Its basic
performances, including a wide energy bandpass of 10-600 keV, energy
resolutions of ~4 keV (FWHM) at 40 keV and ~11% at 511 keV, and a high
background rejection efficiency, have been confirmed by extensive in-orbit
calibrations. The long-term gains of PIN-Si diodes have been stable within 1%
for half a year, and those of scintillators have decreased by 5-20%. The
residual non-X-ray background of the HXD is the lowest among past non-imaging
hard X-ray instruments in energy ranges of 15-70 and 150-500 keV. We provide
accurate calibrations of energy responses, angular responses, timing accuracy
of the HXD, and relative normalizations to the X-ray CCD cameras using multiple
observations of the Crab Nebula.
