"If the allegations are true, yes," the Michigan Republican said when asked if the allegations are grounds for impeachment.
"But everybody in this country gets a fair trial, whether it's the president or anyone else," he added, after leaving a closed-door House GOP Conference meeting on Capitol Hill.
As of Wednesday, no other Republican member of Congress has floated the idea of impeachment.
Amash reiterated that he thinks Congress needs to establish an independent commission to investigate Russia's interference in the 2016 U.S. election and has signed onto Democratic-sponsored legislation that would do just that.
Asked whom he trusts if it's Comey's word against the president's word, Amash said, "I think it's pretty clear that I have more confidence in Director Comey."
A few House Democrats, including Rep. Al Green, D-Texas, have said that the president's actions are an impeachable offense.
"I rise today with a sense of responsibility and duty to the people who have elected me, a sense of duty to this country, a sense of duty to the Constitution of the United States of America," Green said on the House floor. "I rise today, Mr. Speaker, to call for the impeachment of the President of the United States of America for obstruction of justice."
CBS News' Walt Cronkite contributed to this report.