To obtain a small, low cost, and highly stable solid-state laser apparatus capable of realizing femtosecond CW mode locking. In a mode-locked laser apparatus having a resonator which includes a solid-state laser medium (15), a saturable absorption mirror (16), and a negative dispersion element (17) therein, the solid-state laser medium (15) and the saturable absorption mirror (16) are disposed at a distance not greater than twice a Rayleigh length determined by the beam radius of oscillation light formed on the saturable absorption mirror (16). The apparatus further includes a dichroic mirror (13), inside of the resonator, that reflects excitation light (10) inputted from a direction that crosses the optical axis of the resonator toward the solid-state laser medium (15) and transmits oscillation light (18).