Intraparticle distribution of adsorbate amount in cyclic adsorption and desorption is simulated by two methods: rigorous numerical solution of the particle-phase diffusion equation and the linear driving force (LDF) approximation. It becomes clear that the conventional value of 15 D_s/R² as the intraparticle mass transfer coefficient, k_sa_v, in the LDF method is not advisable for the simulation of transient adsorption and desorption. A mass transfer coefficient defined by including the cycle time is thus proposed. In this new conception, k_sa_v increases with decreasing cycle time and approaches π²D_s/R² with increasing cycle time. Simulations of cyclic mode by the LDF method using this new k_sa_v agree well in the steady state with that obtained by numerical solution of the diffusion equation. In unsteady-state operation, however, the two simulations do not coincide with each other because of overestimation of driving force for adsorption and underestimation for desorption in the LDF method.