Chemisorption is more exothermic than physisorption..and so with the increase in temperature chemisorption should decrease..as it happens in the case of physisorption But it increases Why ?

In physisorption there are van-der-waal's or london attractive forces that exist between adsorbate and adsorbent,Whereas,  Chemisorption involves chemical reaction between adsorbate and adsorbent molecules.
As larger amount of activation energy is required to start a chemical reaction, Chemisorption is favoured at higher temperatures.