PURPOSE: To treat chemically the surface of a lamellar material uniformly by supporting a rear side of the lamellar material to be chemically treated, directing the surface thereof downward and running the lamellar material through the inside of a treatment soln. in this state.

CONSTITUTION: A rear side of a wafer 2 is adsorbed with a chuck 21 via a packing 22 and this unit is transferred right with a motor 34 transferring on a rail 35. Since a rail 38 is descended in the upper part of a treatment vessel 31, a pin 37 fixed to the unit is descended and the unit is descended to immerse the wafer 2 into a treatment liquid in the treatment vessel 31. The chuck 21 is rotated in this state and also the treatment liquid is stirred with the magnetic stirrers 32 and the rotors 33. Furthermore when the unit is transferred right, the unit is ascended because the rail 35 is ascended and the wafer 2 is taken out from the treatment liquid to finish the chemical treatment. Thereby the chemical treatment of the surface of the wafer 2 can be continuously performed uniformly.