A seat plate washing apparatus is provided, which washes a seat plate while moving along the seat plate and makes the seat plate hygienic in use. A seat plate washing apparatus comprises: a washing member(110) washing the seat plate of the toilet; and a guide unit(140) in which the washing member is slid along the seat plat. The guide unit comprises: a first guide rail(141); a second guide rail(142); guide blocks which are inserted into the guide rail so that the casing can be slid along the seat plate; and wheels(145) making the sliding of casing facilitated. The washing member comprises: a washing roller(111) washing the seat plate when the first guide block is slid along the first guide rail; a wiper(112) wiping the moisture of the seat plate; and a rinse solution feed vessel(114) supplying the rinse solution.
