An authentication information managing method performed by an information processing device, the authentication information managing method comprising: storing each of at least one application identifier, each of at least one user identifier, each of at least one password, and each of at least one distance in association with each other to a memory, each of the at least one distance indicating each number of key events between each input field for each of the at least one user identifier and each input field for each of the at least one password in each application identified by each of the at least one application identifier; when a specified application having a plurality of input fields is running and the specified application is identified by a specified application identifier of the at least one application identifier, detecting a first input field for a specified password among the plurality of input fields based on a specified attribution that is associated with the first input field, the specified attribution indicating that the first input field is used for a password that is the same for each application and being detected from outside the specified application, the specified password being associated with the specified application identifier in the memory; inputting the specified password to the first input field; detecting a second input field for a specified user identifier among the plurality of input fields based on a specified number of key events associated with the specified application identifier in the memory, the specified user identifier being associated with the specified application identifier in the memory; and inputting the specified user identifier to the second input field. storing each of at least one application identifier, each of at least one user identifier, each of at least one password, and each of at least one distance in association with each other to a memory, each of the at least one distance indicating each number of key events between each input field for each of the at least one user identifier and each input field for each of the at least one password in each application identified by each of the at least one application identifier; when a specified application having a plurality of input fields is running and the specified application is identified by a specified application identifier of the at least one application identifier, detecting a first input field for a specified password among the plurality of input fields based on a specified attribution that is associated with the first input field, the specified attribution indicating that the first input field is used for a password that is the same for each application and being detected from outside the specified application, the specified password being associated with the specified application identifier in the memory; inputting the specified password to the first input field; detecting a second input field for a specified user identifier among the plurality of input fields based on a specified number of key events associated with the specified application identifier in the memory, the specified user identifier being associated with the specified application identifier in the memory; and inputting the specified user identifier to the second input field.