Abstract: A tumbler lock securing device that can be applied to the double casement windows and doors without altering of the casement structure but can be simply detachably placed over opposing window or door handles in their depending latched positions and locking ratchet arms squeezed through a tumbler lock and pawl mechanism. Pawl levers are upwardly spring pressed toward ratchet teeth on the bottom edges of the locking arms that respectively extend in opposite directions and are released only with a key that turns the tumbler lock centerpiece and a depressible cam fixed thereto that acts upon one of two pawl levers but through an interlock arrangement between one of the pawls and the other so that upward spring action for the both pawls is served by but one compression spring. The lock and pawl mechanism can be separated from the locking arms or can be left locked to one of the casement handles when unlatched.