We present the results from the Hitomi Soft Gamma-ray Detector (SGD)
observation of the Crab nebula. The main part of SGD is a Compton camera, which
in addition to being a spectrometer, is capable of measuring polarization of
gamma-ray photons. The Crab nebula is one of the brightest X-ray / gamma-ray
sources on the sky, and, the only source from which polarized X-ray photons
have been detected. SGD observed the Crab nebula during the initial test
observation phase of Hitomi. We performed the data analysis of the SGD
observation, the SGD background estimation and the SGD Monte Carlo simulations,
and, successfully detected polarized gamma-ray emission from the Crab nebula
with only about 5 ks exposure time. The obtained polarization fraction of the
phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1
$\pm$ 10.6)% and, the polarization angle is 110.7$^o$ + 13.2 / $-$13.0$^o$ in
the energy range of 60--160 keV (The errors correspond to the 1 sigma
deviation). The confidence level of the polarization detection was 99.3%. The
polarization angle measured by SGD is about one sigma deviation with the
projected spin axis of the pulsar, 124.0$^o$ $\pm$0.1$^o$.