The inquiry will look at historical abuse of children in care in Scotland.
But John Findlay, who was abused while a pupil in the care of Aberlour House in Moray, said money would be better spent supporting victims.
He said the inquiry was "yet another process" rather than progress towards helping people.
Mr Findlay told BBC Scotland's Timeline programme how he had spoken publically before about what happened to him, but has not been contacted about giving evidence to the inquiry.
He was abused by one of his teachers, who is no longer alive, at Aberlour House, a prep school for Gordonstoun private school in Moray which Mr Findlay went on to attend.
Mr Findlay was assaulted in his bed in a dormitory after being given what he described as a form of date rape drug.
"He fondled my genitalia. He put his head under the covers, He took photographs," said Mr Findlay of the attack.
"Once I was able to move afterwards I confronted him about it. I was convinced by him that I imagined it, that nothing happened."
Mr Findlay said what happened to him as a child "tainted" his adult life, including work and personal relationships.
On the inquiry, he said: "I would love to say I have hope, however, it is yet another announcement of yet another inquiry and yet another process.
"I see actually no progression whatsoever with regards to any government or any school providing genuine help for victims of abuse.
"It is all very well saying 'yeah, we are looking into it', but for crying out loud it is about time you could just turn around and say instead of spending how ever much on inquiries why not just spend the money on helping the victims of this abuse."
Gordonstoun is among boarding schools and other institutions involved in the investigation.
In a statement. Gordonstoun said: "We welcome the Scottish Abuse Inquiry's invitation to submit a report and will respond in full.
"Cases of non-recent abuse must be unimaginably distressing for the victims and their families and the work that the Scottish Abuse Inquiry is undertaking will, we hope, draw important lessons from the past and make children safer in the future.
"For everyone at Gordonstoun today, making sure our students are happy, healthy and safe is at the heart of everything we do.
"We are committed to providing a safe and nurturing environment for all our students. Our ongoing work in this area was recognised in our most recent independent Care Inspectorate Report which gave us a rating of five -  'very good' - for pupil care and support and noted the 'comprehensive child protection procedures' in place."
The Scottish government said it had established one of the widest ranging public inquiries that Scotland has ever seen into the abuse of children in care.
A spokesperson said: "It will focus on the systemic institutional failures which saw many of our most vulnerable children, including those in the care of the state, abused by the very individuals who were there to care for them.
"We want that inquiry to be able to undertake its work in a timescale that can address the issues raised by survivors.
"Scotland is one of the few countries in the world that has dedicated funding for support services for adult survivors of child abuse.
"We have made real progress in delivering what survivors told us they wanted, including a greatly expanded support fund of Â£13.5m over five years to co-ordinate access to and deliver resources, integrated care and support for those who were abused in care."
The spokesperson said Deputy First Minister John Swinney had also committed to a consultation on redress, pledging to work with survivors to consider the wide range of differing views on the subject.
The spokesperson added: "Last year, we introduced legislation to make it easier to take civil action against historic child abuse, and we also reviewing the child protection system to ensure it is as effective as it can be."
A victim of child abuse has criticised the decision to hold an inquiry to investigate more than 60 institutions, including several top private schools.