Asked in the interview with Germany's Spiegel news weekly about the divergences between his tough stance on Athens and the more flexible approach of Chancellor Angela Merkel, the veteran politician admitted to “differences of opinion”.
“That's part of democracy,” he said.
For Schäuble, “each has their role to play.”
He signaled he would offer to quit if he concluded he no longer had a say in her government.
“Angela Merkel is chancellor, I am finance minister. Politicians derive their responsibility from their functions. No one can force them. If someone tried I could go to the president (Joachim Gauck) and ask him to dismiss me.”
Asked if he was thinking about resigning, he replied: “No, what makes you think that?”.
Schäuble said he and Merkel had an understanding: “We know we can count on each other.”
So far Merkel has been able to draw on Schäuble's popularity among members of her conservative-social democrat coalition to garner grudging acceptance for a third Greek bailout.
On Friday, a large majority of lawmakers in the lower house of parliament gave Merkel the green light to start talks on the new rescue package — but 60 members of her conservative CDU/CSU faction voted against.
Schäuble, a figure of hate in Athens where he sparked fresh outrage last weekend by floating the idea of Greece taking “time out” from the euro, described the new bailout plan as the “last attempt” to put Greece's finances to rights.
At home, his hawkish stance has played well with voters.
A poll in early July showed 72 percent of Germans supporting his approach.