Patent ID: 7668221

Claim:
A gas laser apparatus comprising: a laser oscillating section including a blower forcibly circulating a medium gas in a medium circuit; and a blower monitoring section monitoring a maintenance state of said blower; said blower comprising: a lubricant storage chamber storing a lubricant; and a lubricant monitoring chamber connected to said lubricant storage chamber to ensure fluidic communication therebetween at a position lower than an oil level of a lubricant having a predetermined appropriate volume and stored in said lubricant storage chamber; said blower monitoring section comprising: a lubricant detecting section detecting that a lubricant stored in said lubricant storage chamber of said blower flows into said lubricant monitoring chamber and at least a part of the lubricant is present in said lubricant monitoring chamber, as a result of internal-pressure change in said lubricant storage chamber; and a lubricant-change judging section monitoring whether said lubricant detecting section detects a presence of said lubricant in said lubricant monitoring chamber, before said laser oscillating section is activated, and judging that, when said lubricant detecting section does not detect said presence, said lubricant stored in said lubricant storage chamber is in a state immediately after a lubricant change.