The Police Investigations & Review Commissioner (PIRC) assessed the use of the devices in its 2018-19 annual report after human rights groups raised concerns about the potential for them to be misused or overused.
Police Scotland announced plans to train and equip more officers with tasers in December 2017.
It trained and equipped around 500 so-called specially trained officers (STOs), who were then routinely armed with the devices from June 2018 onwards.Over the period of the report, between April 2018 and March 2019, PIRC assessed 34 uses of Tasers and went on to investigate seven of the incidents fully.
It found that in all but one of the seven investigations the use of Tasers had been "necessary, justified and proportionate".
The report said: "Unsurprisingly, STOs often used Tasers when confronted with people armed with weapons such as knives, machetes, firearms and crossbows.
"On other occasions, they used them when being threatened with violence.
"Generally, it appears that the use of Tasers by Police Scotland's STOs increased their safety and allowed them to resolve incidents quickly without having to call upon the force's limited number of specialist firearms officers.
"We also observed that the use of Tasers had often helped to save the lives of people with mental health issues threatening to commit suicide or self-harm using weapons.
"In these circumstances, the officers were able to limit the self-harm or even prevent the death of these individuals."
John McSporran, head of investigations at PIRC, said: "In the vast majority of incidents where Tasers were used by specially trained officers, it has allowed them to resolve incidents swiftly, increasing officer and public safety, which is very reassuring."
The report also found policing bodies and the Crown Office and Procurator Fiscal Service (COPFS) referred 508 incidents to PIRC in 2018-19, an increase of 21 per cent on the previous year's figure of 421.
All of them were thoroughly assessed and 67 were taken to a full investigation, it said.The report also found policing bodies have implemented 98% of all recommendations made by the PIRC review team in 2018-19.