To treat a wafer with a chemical with high planar uniformity even when the wafer has a large diameter.

A developing device 1 which is used as a chemical treating device is provided with a first treating tank 11 filled up with a developing solution 11a as a chemical, a second treating tank 12 filled up with a rinsing solution 12a as a chemical, a holding section 13 which holds a wafer 2 to be dipped in the developing solution 11a contained in the tank 11 and the rinsing solution 12a contained in the tank 12, a rotating section 14 which supports the holding section 13 and, at the same time, rotates the section 13 so that the surface of the wafer 2 held by the section 13 can be faced to the surfaces of the solutions 11a and 12a while the section 14 supports the section 13, an elevating/lowering section 15 which supports the section 14 and, at the same time, moves the section 14 in the vertical direction against the surfaces of the solutions 11a and 12a, and a control section 17 which controls the rotation of the section 13 by means of the section 14 and vertical movement of the section 14 by means of the section 15.