To suppress the dispersion of impregnation concentrations to be small by uniformly impregnating a catalyst solution to a catalyst carrier.

A device has a cylindrical rotary barrel 2 which is filled with the catalyst carrier P, and a catalyst supply pipe 3 penetrating through the rotary barrel 2 and for supplying the catalyst solution R inside thereof. The rotary barrel 2 is rotatably and roughly horizontally supported around the catalyst supply pipe 3. The catalyst supply pipe 3 has a plurality of splay nozzles 5 being directed in a roughly vertical and downward direction, which are spaced at regular intervals in the longitudinal direction. On the inner peripheral wall face 2b of the rotary barrel 2, a weir 4 extending in the radial direction is provided along the axial direction of the rotary barrel 2.