The Senate has 150 members -- 76 elected, one from each province, and 74 appointed in a selection process. At present there are only 146 serving senators. The new speaker was required to get at least half, or 73 supporting votes.
The selection of a new Senate Speaker selection was held after Gen Teeradej Meepian lost the post when a court sentenced him to jail last month.
The Criminal Court on July 25 found Gen Thiradet guilty of illegally awarding himself and two subordinates a pay increase when he was chief ombudsman in 2004 and sentenced him to two years jail, suspended for two years.
Gen Thiradet was disqualified as Senate speaker under the Article 124 (4) of Constitution which states that the Senate speaker must be disqualified once given a jail term, regardless of whether imprisonment is suspended or not.
The vote was chaired by second deputy senate speaker Pornthip Lohveera Chanrattanapreeda.
Four senators were nominated as contenders -- two elected senators, Mr Nikom from Chachoengsao and Kecha Saksomboon from Ratchaburi; and two appointed senators Mr Pichet and Sunan Singsomboon.
After the nomination, the four candidates had 10 minutes each to clarify their vision if elected to the top job of the senate.
In the first round of secret voting, Mr Pichet placed first with 63 votes, followed by Mr Nikom with 46, Mr Kecha with 35, and Ms Sunan with two votes.
The first two candidates, Mr Pichet and Mr Nikom, competed in the second round of voting and Mr Nikom beat Mr Pichet with 77-69 votes.
After the vote, Mr Nikom thanked senators who supported him, promised neutrality and said that he would not give in any pressure.