A solid-state laser device includes: a first water tank which houses a laser rod and a lamp and into which coolant is introduced; an outer inlet which is provided in a member forming a chamber and through which coolant is received into the chamber; and an outer outlet provided in said member and through which a coolant is discharged to the outside of the chamber. The solid-state laser device further includes: two second water tanks that house electrodes of both ends of the lamp, respectively, and communicate with the first water tank; a coolant inflow passage of which one end communicates with the outer inlet and the other end forms inner inlets opened to only the second water tanks; and a coolant outflow passage of which one end communicates with the outer outlet and the other end forms an inner outlet opened to the first water tank.