The juntaappointed NLA will cease functioning as the upper chamber today, coinciding the senatorial election.
"The world has changed a great deal and I feel like a dinosaur," Meechai said.
He admitted that he was no longer fit to serve in the legislative duty because of his old age.
"I don't feel eager for political participation as before and I have found what I used to think and do is no longer compatible with modernday politicking," he said.
He said he would let go instead of getting involved in the political scene.
He said he hoped his legislative contributions would help to steer the country on the right tract.
Following his farewell speech, he talked to reporters informally.
He said he would not accept to lead the legislative branch if there would be another coup or under any circumstances, pointing out that he is now 70 years old.
He said he was completely unaware of the September 19 coup until a group of four officers paid him a visit at home around 9 pm.
"I think I got the job as NLA speaker by accident because ajarn Bowornsak Uwanno was in France at the time," he said.
He said he was the last to know about every coup and that he later became involved in the legislative duty following the power seizure because he was "unlucky" to be sought for his legal opinions to put the political system back on tract.
Asked to comment on the September 19 coup, he said it was a "most lame" incident.