An electric connection box includes a housing, a first lid portion, a groove and a water stop wall. The housing includes an opening. The first lid portion includes a first body wall that closes the opening of the housing, and a first peripheral wall extending from a periphery of the first body wall toward the housing. The groove is provided between the first peripheral wall and a wall portion arranged to be spaced apart from the first peripheral wall. The water stop wall is provided on the first lid portion and configured to cover an opening of two ends of the groove in a longitudinal direction.