Inflation, taxes and government regulation are the biggest problems faced by small businessmen, according to Milton Stewart. who will be sworn in today as the first chief counsel for advocacy of the Small Business Administration.

In his role as advocate for the nation's small businessmen. Stewart hopes to make the tax structure more favorable to investment in small business, he said in an interview yesterday.

The cumulative impact" of all taxes on a small business puts them at an "inequitable disadvantage. Very serious questions can be properly raised and we intend to raise them, as to whether (existing tax laws) leave people enough incentives ... to enter small business," he added.

Stewart's nomination to the new SBA post was endorsed by more than 100 small business groups but he came under fire for alleged technical violations of federal securities laws while president of Creative Capital Corp.

Both the Securities and Exchange Commission and SBA found Stewart's firm had violated laws and in 1974, Stweart signed a SEC consent agreement to end staff charges of violations without admitting or denying the allegations.

Despite objections of some senators, Stewart's nomination was approved 83-11 by the Senate last week.

Stewart 56, said he expects he will be unable to help small businessmen with inflation, but he hopes to reduce the burden of federal regulation on small businesses. He said small businesses often are hurt by regulations which were intended just for big businesses. Federal regulators look like "an endless parade" to the small businessman, and are "terribly important in affecting the entrepreneurial climate," Stwart continued.

As small business advocate, Stewart's chief responsibility will be to be present the small businessman's view in policymaking decisions of federal agencies and to Congress, he said. He will have a staff of about 100 persons in the SBA, including 35 new employes.

Stewart said he is confident the Carter administration "wants small business to grow as much as possible." He mentioned a White House conference scheduled for 1980 designed "to build a new awareness of the importance of small business in the national economy."

Stewart said he also is pleased by a June 14 letter from President Carter directing the head of each executive branch department and agency to develop an "initiative" showing how the agency is working to improve the relationship between the government and the small business sector.

"The White House conference and the President's letter give us the machinery to speed up what would otherwise take many, many years to get done," Stewart declared.

Stewart said his main duties would be to inform small businesses of the federal programs that affect them, act as an ombudsman and spokesman within the government for small businesses, suggest policy changes to government agencies and conduct research about the position of small business with the economy.