A semilinear self-pumped phase-conjugate mirror was successfully formed using two crystals of copper doped (K0.5Na0.5)0.2(Sr0.61Ba0.39)0.9Nb2O6 (Cu:KNSBN). The self-pumped phase-conjugate mirror was formed simply by an incident Ar+ laser beam (λ=488 nm) similar to the conventional Cat type self-pumped phase-conjugate mirror. The phase-conjugate reflectivities were investigated as a function of the incident beam position and the incident beam angle. The acceptable conditions of the incident beam position and angle for the self-pumped phase-conjugate mirror were 2.6 and 1.5 times wider, respectively than those of the normal Cat type self-pumped phase-conjugate mirror.