Electrical connection box

An electrical connection box including a relay, a bus bar connected to the relay, the electrical connection box comprising:

• a case including an attachment portion for the relay, wherein the case includes a first case including the attachment portion;
• a second case that covers at least a part of the attachment portion of the first case and is configured to form a single piece with the first case;
• a cover covering a connection portion between the relay and the bus bar, wherein the cover includes, on the second case side, an opening through which the bus bar is passed between the relay and the cover;
• wherein the cover includes a wall portion and an engaging portion that is provided at a part of the wall portion and prevents the cover from coming off by engaging with a part of the attachment portion, and
• the attachment portion includes a stopper portion for suppressing displacement of the part of the wall portion in a direction in which the engaging portion is disengaged.