  We report that the pressure-temperature phase diagram of single-crystalline
SrFe$_2$As$_2$ is easily affected by the hydrostaticity of a
pressure-transmitting medium. For all of the three mediums we used,
superconductivity with zero resistance appears, accompanied by the suppression
of an antiferromagnetic (orthorhombic) phase, but the critical pressure $P_c$
was found to depend on the type of medium. $P_c$ was estimated to be 4.4 GPa
under almost hydrostatic condition, but it decreased to $3.4-3.7$ GPa with the
use of the medium already solidified at room temperature. The uniaxial stress
along the c-axis is suggested to aid in the suppression of the
antiferromagnetic (orthorhombic) phase. The pressure effect of BaFe$_2$As$_2$
is also reported.
