Locking construction of electric connection box

A locking construction of an electric connection box having an upper casing and a lower casing, one of the upper and lower casing telescoping into the other, said locking construction comprising:

• a locking claw provided on an outer surface of a first side wall of said one of the upper and lower casings;
• an engageable portion which is provided on an inner surface of a second side wall of the remaining one of the upper and lower casings, such that the locking claw is brought into engagement with the engageable portion as the first side wall travels in a first axial direction to telescope into the second side wall, and locks the first side wall with respect to the second side wall to prevent the upper and lower cases from being separated from one another in a direction opposite from said first axial direction;
• an L-shaped projection provided on the outer surface of the first side wall in the vicinity of the locking claw;
• said L-shaped projection including a base portion extending from the first side wall and a bent portion extending from the base portion;
• and
• a notch formed in an edge face of the second side wall such that the base portion of the L-shaped projection is inserted into the notch as the the first side wall telescopes into the second side wall;
• wherein when the base portion of the projection has been inserted into the notch, the second side wall is gripped between the bent portion of the projection and the first side wall, preventing the outward deflection of the second side wall from the first side wall in a direction other than said first axial direction.