A clogging degree estimation apparatus includes an information acquisition unit configured to acquire information indicating a vehicle's traveling status for each predetermined travel section, a coefficient determination unit configured to determine a clogging coefficient K based on the traveling status indicated by the information for each travel section, and a clogging degree calculator configured to calculate an increase in clogging degree based on the product of the clogging coefficient K and a distance of the travel section for each travel section and calculate, as the clogging degree, an integrated value of the increase in clogging degree calculated for each travel section.