This paper describes a prototype of a linear reciprocating magnetic refrigerator using a gadolinium parallel plate. The new design of the regenerator, installation, and experiment is presented. The regenerator consists of a gadolinium plate and an inlet/outlet section. The thickness and length of the gadolinium plate are 1mm and 80mm, respectively. The gap between parallel plates is 0.1mm. Water is used as the heat transfer fluid. The permanent magnet structure used in the present study can generate a maximum magnetic field intensity of 0.94 T. The effects of surface roughness of the gadolinium parallel plate on the temperature span and cooling capacity are investigated. The results show that there is no significant effect of surface roughness on the magnetic refrigerator performance at a high utilization factor. The results from the present study are important for the design of magnetic refrigerators operating at room temperature.