The present disclosure provides a ring adjuster. The ring adjuster includes an adjuster main body, at least one locking structure, a first side wall and a second side wall. The adjuster main body is arc-shaped, the first side wall and the second side wall are connected with two opposite sides of the adjuster main body respectively. The adjuster main body includes an inner surface and an outer surface, the inner surface is configured to contact with a user's finger, the outer surface is configured to contact with a ring. The locking structure crosses the first side wall and the second side wall such that a locking chamber is formed between the outer surface and the locking structure to contain the ring.