An optically pumped disk type solid state laser oscillator includes: a cylindrical shape thin film laser gain medium having a through-hole; a ring mirror whose surface is opposing to a side surface of the thin film laser gain medium; a conical mirror arranged in the through-hole and reflects a light from the ring mirror to a direction perpendicular to the thin film laser gain medium where an output mirror is arranged. The ring mirror, the conical mirror and the output mirror compose a resonator for oscillating a laser beam to be outputted from the output mirror.