A laser fiber 1 is wound around an outer peripheral face 2a of a glass cylindrical member 2 serving as a structural member which can confine excitation lights L 1 and L 2 for exciting the laser fiber 1. The excitation lights L 1 and L 2 from laser diodes 41 and 42 impinge on the vicinity of the outer peripheral end portion of an end face 2b of the glass cylindrical member 2, through prisms 31 and 32, and confined by repeating total reflection at the inner side face of the outer peripheral face 2a. The confined excitation lights are introduced into the laser fiber 1 through portions contacted with the glass cylindrical member 2, thereby causing excitation.