A disconnection mechanism for a dark current fuse provides a connecting terminal connecting the dark current fuse, a fuse block body receiving the connecting terminal, and a fuse holder slidably engaged with the fuse block body in a direction of connecting the dark current fuse, the fuse holder provides a cutaway opening exposing a head of the dark current fuse being therein, an engaging projection disposed at an opening edge of the cutaway opening for engaging the head, and a supporting wall portion contacting a trunk of the dark current fuse. The disconnection mechanism is not necessary to store the extracted dark current fuse after a dark current fuse circuit is opened, so that there arises no possibility of missing the extracted dark current fuse, the dark current fuse can be extracted by using a puller, and the dark current fuse is surely held and prevented from slipping off.