  A ferromagnetic-paramagnetic phase transition of the two-dimensional
frustrated Ising model on a hyperbolic lattice is investigated by use of the
corner transfer matrix renormalization group method. The model contains
ferromagnetic nearest-neighbor interaction J_1 and the competing
antiferromagnetic interaction J_2. A mean-field like second-order phase
transition is observed when the ratio \kappa = J_2 / J_1 is less than 0.203. In
the region 0.203 < \kappa < 1/4, the spontaneous magnetization is discontinuous
at the transition temperature. Such tricritical behavior suggests that the
phase transitions on hyperbolic lattices need not always be mean-field like.
