1. An exhaust emission purification controller of an internal combustion engine, the engine including aft exhaust passage and an exhaust gas purifying catalyst arranged in the exhaust passage, the controller performing a bed temperature control in which a bed temperature of the exhaust gas purifying catalyst is adjusted to a target bed temperature through addition of unburned fuel to exhaust gas, wherein, when carrying out the bed temperature control, the controller learns a learned value of an addition amount of the unburned fuel so as to correct a difference between the bed temperature, which is detected periodically, and the target bed temperature, the controller comprising: a determining section that is configured to determine whether a flow of exhaust gas to the exhaust gas purifying catalyst is in a steady state; a storage section that is configured to store the learned value as a steady state learned value when the determining section determines that the flow of the exhaust gas is in the steady state, and stores the learned value as a transient state learned value when the determining section does not determine that the flow of the exhaust gas is in the steady state; a reflecting section that is configured to reflect at least the transient state learned value out of the steady state learned value and the transient state learned value in the addition amount of fuel when the bed temperature control is carried out; and a control executing section that is configured to execute a control based only on the steady state learned value out of the steady state learned value and the transient state learned value.