To provide a wafer processing apparatus and a wafer processing method where atmosphere being generated from a supply means in standby does not affect a wafer that has been treated, and wafer processing atmosphere and atmosphere being generated from other supply means do not contaminate the supply means.

In the wafer processing apparatus having a retention means 59 for retaining a wafer W, and a supply means 50 for supplying processing liquid or a treatment gas to the wafer W being retained by the retention means 59, an outer chamber 43 for surrounding the retention means 59 is provided, a supply means 50 is provided outside the outer chamber 43, and an opening 48' is provided at the outer chamber 43, where the opening 48' can be opened and closed to allow the supply means 50 to carry it in and carry it out.