A power circuit interrupting device including a first housing including a pair of fixed electrodes and a fuse having terminals at both ends thereof, and a second housing including a moveable electrode, the moveable electrode interrupting electrical connection between the fixed electrodes when the second housing is uncoupled from the first housing, and establishing the electrical connection between the fixed electrodes when the second housing is coupled with the first housing. The first housing has an opening provided for carrying out a continuity test for the fuse. The opening is always covered with the second housing in a condition that continuity of a circuit is allowed. The power circuit interrupting device serves to facilitate the continuity test for the fuse built therein and comply with such a maintenance procedure that the continuity test should be carried out after interrupting continuity of the power circuit.