A drawer locking apparatus of a cabinet, including a cabinet body, at least one drawer slidably disposed in the cabinet body, a base seat mounted in the cabinet body, a slide section slidably fitted in the base seat, an engaging section and a dogging device. One end of the engaging section is disposed on the slide section. The other end of the engaging section has a hook plate with a guide slope for hooking rear sideboard of the drawer. The dogging device serves to drive the slide section to slide between a first position and a second position.