A linear Fresnel concentrating solar device was developed and its performance was studied. Various combinations of reflecting mirrors were tried to achieve the temperature at focus. A tubular absorber made from aluminium pipe (0.075 m diameter and 0.53 m long) filled with Hytherm-500 oil was used. The absorber tube was placed at focus of the collector. The quantum of heat absorbed by oil in absorber tube with 10, 15, and 20 numbers of mirrors was evaluated. Rise in oil temperature in absorber tube with different set of reflecting mirrors was compared. The efficiency of this solar device with different set of mirrors was also compared. It was observed that increase in peak oil temperature in absorber tube was not directly related with number of mirrors. The overall efficiency of the concentrator during initial 30 min of operation with 10, 15 and 20 number of mirrors was found to be 20.5, 17.6 and 16.8% respectively.