category.phpにおいて、the_post()の前に以下を記述する。
if (is_category()) { $current_cat = get_query_var('cat'); if ($children = get_categories('child_of='.$current_cat)) { $exclude = array(); foreach ($children as $child) $exclude[] = $child->term_id; query_posts(array('cat'=>$current_cat, 'category__not_in' => $exclude)); } }