To assemble a solid-state laser having less variation of laser properties by suppressing the distortion of a holding member due to the bonding of an optical element and the holding member in a laser, wherein the temperature of a resonator is controlled to be constant for stabilization.

After a plurality of optical elements 13, 14, 15 and 17 are bonded to fix to prescribed positions of a resonator unit 21 consisting of an optical element holding part of metal, the optical axis of a concave mirror 16 is so adjusted as to obtain the maximum output of a semiconductor laser 11. After adjusting the optical axis, the temperature of the laser is controlled to the optimum control temperature with a Peltier element 31, and then bonding agent is poured into between a resonator mirror 16 and a member holding it, and then the bonding agent is cause to cure to fix the resonator mirror 16.