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 Ho3+, Sm3+, Eu3+, Dy3+, Er3+, and Tb3+ 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 5S2 to 5I7, from 5S2 to 5I8, from 4G5/2 to 6H5/2, from 4G5/2 to 6H7/2, from 4F3/2 to 6H11/2, from 5D0 to 7F2, from 4F9/2 to 6H13/2, from 4F9/2 to 6H11/2, from 4S3/2 to 4I15/2, from 2H9/2 to 4I13/2, and from 5D4 to 7F5. The above solid-state laser crystal or optical fiber is excited with a GaN-based compound laser diode.