A steering control device includes a transverse gradient estimator configured to estimate a transverse gradient of a road surface on which a vehicle travels; an assisting amount calculator configured to calculate a first assisting amount based on the transverse gradient; a low pass filter configured to perform a low pass filter processing for the first assisting amount, and output the processed first assisting amount subjected to the low pass filter processing, as a second assisting amount; and a motor controller configured to control a motor that generates a steering assist torque, using the second assisting amount. The low pass filter switches a cut-off frequency of the low pass filter between a first cut-off frequency and a second cut-off frequency that is set to a value higher than the first cut-off frequency, depending on whether the second assisting amount increases with time or the second assisting amount decreases with time.