A solid-state laser crystal constituting a laser-diode-excited solid-state laser apparatus or an optical fiber constituting a fiber laser apparatus or fiber laser amplifier is doped with one of Ho<3+>, Sm<3+>, Eu<3+>, Dy<3+>, Er<3+>, and Tb<3+> so that a laser beam is emitted from the solid-state laser crystal or the optical fiber, or incident light of the fiber laser amplifier is amplified, by one of the transitions from <5>S2 to <5>I7, from <5>S2 to <5>I8, from <4>G5 / 2 to <6>H5 / 2, from <4>G5 / 2 to <6>H7 / 2, from <4>F3 / 2 to <6>H11 / 2, from <5>D0 to <7>F2, from <4>F9 / 2 to <6>H13 / 2, from <4>F9 / 2 to <6>H11 / 2, from <4>S3 / 2 to <4>I15 / 2, from <2>H9 / 2 to <4>I13 / 2, and from <5>D4 to <7>F5. The above solid-state laser crystal or optical fiber is excited with a GaN-based compound laser diode.