Smith, Judge.

This case is an action on a promissory note. The defendant admitted the execution of the note sued upon but set up affirmative defenses of res judicata or estoppel by judgment based upon a prior judgment in favor of defendant upon an action on a note of the same amount, and the defense that a new note and cash payment had been accepted by the plaintiff in settlement of, and in novation of, the note sued upon. Plaintiffs motion for summary judgment was sustained by the trial judge and defendant appeals. Held:

1. The defenses pleaded were sufficient to admit of proof in support thereof.

2. On motion for summary judgment by a plaintiff, the burden was upon the plaintiff to produce evidence of the necessary certitude, that is, that demanded a finding as a matter of law, that the defenses so pleaded were untrue. No such proof was offered. See Stratton & McLendon v. Cameron-Brown Co., 140 Ga. App. 430. See Roberson v. Evergreen & Associates, Inc., 134 Ga. App. 881 (216 SE2d 693). The deposition of the defendant taken by the plaintiff fails to accomplish this purpose.

3. Accordingly, the motion of the plaintiff, treated either as a motion for judgment on the pleadings or as a motion for summary judgment, was improperly sustained.

Judgment reversed.

Bell, C. J., and McMurray, J., concur.