If they can use their hands skillfully to some extent, holding the lunch box is possible, however, small children who go to kindergarten or nursery school sometimes can't hold the lunch box skillfully.
ある程度、手が上手に使えるなら弁当箱を持って食事が出来るが、幼稚園や保育園などの幼児では上手に弁当箱を持てない場合もあるためである。