Abstract: Disclosed is A multiple times available drug concentration measuring apparatus including a sample input unit configured to allow a liquid drug sample to be introduced therethrough, a dilution unit configured to add a solvent to a portion of the liquid drug sample in order to dilute the liquid drug sample, a concentration measurement unit configured to measure the concentration of the liquid drug sample using a sensor, and a control unit configured to decide a dilution ratio of the liquid drug sample based on data received from the concentration measurement unit, to perform control such that the dilution unit dilutes the liquid drug sample according to the dilution ratio, and to calculate the concentration of the liquid drug sample based on the dilution ratio and the data received from the concentration measurement unit.