To provide a hard surface treating agent forming a transparent coated film and capable of preventing falling of dew condensation water and attached water formed in droplet state.

The hard surface treating agent comprises 0.01-10 wt.% polysaccharide, 0.001-20 wt.% antiseptic agent and the balance of water. Glucomannan, xanthan gum, gellan gum, carrageenan, sodium alginate, etc., is preferably used as the polysaccharide. Benzoic acid, sodium benzoate, ethyl para-oxybenzoate, etc., is preferably used as the antiseptic agent. The hard surface treating agent further may contain 0.001-20 wt.% alcohols.