  We investigate the functionality of the $\mathrm{Cr}$-doped
$\mathrm{RuO_{2}}$ as an electrode of the magnetic tunnel junction (MTJ),
motivated by the recent experiment showing that $\mathrm{Cr}$-doping into the
rutile-type $\mathrm{RuO_{2}}$ will be an effective tool to control its
antiferromagnetic order and the resultant magnetotransport phenomena easily. We
perform first-principles calculation of the tunnel magnetoresistance (TMR)
effect in the MTJ based on the $\mathrm{Cr}$-doped $\mathrm{RuO_{2}}$
electrodes. We find that a finite TMR effect appears in the MTJ originating
from the momentum-dependent spin splitting in the electrodes, which suggests
that $\mathrm{RuO_{2}}$ with Cr-doping will work as the electrode of the MTJ.
We also show that this TMR effect can be qualitatively captured using the local
density of states inside the tunnel barrier.
