This study examined the effects of the head cooling on the sweat rates in 6 healthy female subjects at an ambient temperature of 28°C and a relative humidity of 60%. The exercising subjects wore protective clothing and a mask for pesticide. Head cooling was made by putting frozen gel strips on the parietal and the front head which were held by a net-bandage (with cooling). On separate days, the same experiments were made without head cooling (without cooling). The total weight of the frozen gel strips was 250 g. After the subjects rested for 15 min in a chair, they repeated three times the work/rest schedule of 15 min exercise on a bicycle ergometer (50 W) followed by 5 min rest. Frozen gel strips were put on the head just before the first exercise bout. Main results were summarized as follows : 1) The forearm sweat rate, heart rate and the changes in T_re from the initial level (ΔT_re) were significantly lower “with cooling” than “without cooling”. 2) The amount of sweat adhered to the clothing ensemble was significantly lower “with cooling” than “without cooling”. 3) The changes in T_ty from the initial level (ΔT_ty) tended to be clearly lower “with cooling” than “without cooling”. 4) Skin temperatures of the forehead and the cheek under a mask tended to be lower “with cooling” than “without cooling”. 5) Subjective. sensation ratings seemed to be improved in most subjects “with cooling”. Thus, it was concluded that head cooling seemed to be more effective in reducing thermal strain in working subjects wearing the protective clothing and a mask for pesticide at hot environments.