Cephonodes armatus is a moth of the family Sphingidae.

It is known from Fiji and the northern Mariana Islands.

It is similar to Cephonodes janus janus but abdominal segments five and six each have a small lateral red spot, or segment five has a complete red belt.

The underside of the abdomen is yellow, greyish medially and laterally reddish.

The forewing upperside has a marginal band.