A brake pad state estimation device that estimates a brake pad state (ST) including at least one of a wear volume (W) and a temperature (Te) of a brake pad of a vehicle , the brake pad state estimation device comprising: a processor ; and a storage , wherein the processor is adapted to execute: an information acquisition process acquiring sensor detection information that includes a vehicle speed (V) and a brake pressure (Pb) detected by a sensor installed on the vehicle ; a brake pad state calculation process calculating the brake pad state (ST) based on the sensor detection information during braking of the vehicle ; an information output process storing a result of calculation of the brake pad state (ST) in the storage and/or transmitting the result of calculation of the brake pad state (ST) to an outside of the vehicle ; characterised by a processing frequency control that variably sets a processing frequency (FP) of at least one of the brake pad state calculation process and the information output process, and in the processing frequency control, the processor is further adapted to set the processing frequency (FP) in a case where the vehicle speed (V) is lower to be lower than the processing frequency (FP) in a case where the vehicle speed (V) is higher, or to set the processing frequency (FP) in a case where the brake pressure (Pb) is lower to be lower than the processing frequency (FP) in a case where the brake pressure (Pb) is higher. a processor ; and a storage , wherein the processor is adapted to execute: an information acquisition process acquiring sensor detection information that includes a vehicle speed (V) and a brake pressure (Pb) detected by a sensor installed on the vehicle ; a brake pad state calculation process calculating the brake pad state (ST) based on the sensor detection information during braking of the vehicle ; an information output process storing a result of calculation of the brake pad state (ST) in the storage and/or transmitting the result of calculation of the brake pad state (ST) to an outside of the vehicle ; characterised by a processing frequency control that variably sets a processing frequency (FP) of at least one of the brake pad state calculation process and the information output process, and an information acquisition process acquiring sensor detection information that includes a vehicle speed (V) and a brake pressure (Pb) detected by a sensor installed on the vehicle ; a brake pad state calculation process calculating the brake pad state (ST) based on the sensor detection information during braking of the vehicle ; an information output process storing a result of calculation of the brake pad state (ST) in the storage and/or transmitting the result of calculation of the brake pad state (ST) to an outside of the vehicle ; characterised by a processing frequency control that variably sets a processing frequency (FP) of at least one of the brake pad state calculation process and the information output process, and in the processing frequency control, the processor is further adapted to set the processing frequency (FP) in a case where the vehicle speed (V) is lower to be lower than the processing frequency (FP) in a case where the vehicle speed (V) is higher, or to set the processing frequency (FP) in a case where the brake pressure (Pb) is lower to be lower than the processing frequency (FP) in a case where the brake pressure (Pb) is higher. <EOS>