In a snap-fit for attaching a second unit to a first unit, an engaging member provided on the second unit includes: a claw configured to restrict movement of the second unit relative the first unit in a removing direction; an elastic support configured to support the claw so as to be movable in a direction intersecting the removing direction and in a releasing direction in which the claw is released from the engagement with an engaged member provided on the first unit; and an operative part provided on the elastic support and configured to release an engagement of the engaging member with the engaged member. The operative part includes at least a portion that overlaps the claw with respect to the removing direction.