PURPOSE: To interlink an engaging member positively with a switch when a cover body is closed, and to conduct pushing operation by installing the engaging member being engaged with a sheathing case and fastening the cover body when the cover body is closed to the cover body while mounting the switch near the engaging section.

CONSTITUTION: A locking pawl 21 is deflected toward the inside of a sheathing case 1 and lowered by the inclination of a locking pawl 11 by turning and pushing a hood 2 in the direction B by an operator when the hood 2 is closed, and the protrusion 21b of the locking pawl 21 rides across on the locking pawl 11 and is engaged with the locking pawl 11. A nose section 21a is interlinked with the operating section 4a of a switch 4 at that time, and pushes the operating section 4a and works it to a position shown in a full line and turns the switch ON, and the state of closing of the hood 2 is detected. When the hood 2 is opened, on the other hand, the operator pushes the base end section of the locking pawl 21 toward the inside of the sheathing case 1 as shown in the arrow C, the protrusion 21b rides across on the locking pawl 11 and the engagement of the locking pawls 11, 21 is released, and the hood 2 is rotated easily in the direction A and opened.