.alpha.-cyanoacrylate compounds expressed by the following general formula: ##STR1## wherein R.sup.1 designates --CH.sub.2 -- or ##STR2## and R.sup.2 designates alkyl groups, alkenyl groups or alkynyl groups of C.sub.1 to C.sub.4. These compounds are preferably synthesized by the reaction of the compounds expressed by the following general formula: ##STR3## wherein R.sup.1 and R.sup.2 are same as the above described, with formaldehyde products and then the depolymerization of the resulting dehydrating condensation polymers. These compounds are effectively used as fast-setting adhesives.