A mode-locked solid-state laser apparatus having a resonator which includes a solid-state laser medium, a saturable absorption mirror, and a negative group dispersion element therein, in which the solid-state laser medium and the saturable absorption mirror are disposed at a distance not greater than twice a Rayleigh length which is determined by the beam radius of oscillation light formed at the saturable absorption mirror. The apparatus further includes a dichroic mirror in the resonator that reflects excitation light inputted from a direction crossing the optical axis of the resonator toward the solid-state laser medium and transmits oscillation light.