To develop an adsorbent for use in an adsorption heat pump (AHP), active carbons were produced by low-temperature KOH and NaOH chemical activation using polycarbonate, a kind of engineering plastic. Water vapor adsorption isotherms were measured on activated carbons formed under similar experimental conditions to those reported in our last paper but with several activation times (1-10 h). It was found that the best activated carbons adsorb about 2 times more water vapor absorbed than silica gel in the AHP operation range (phi: 0.1-0.35). It was also found that the optimum conditions in the present experiments were similar to those of the last report (R=3.2, T-a=773 K), but activation time using NaOH was shorter than that using KOH. These results show that the possibility of producing activated carbon for AHP by these methods.