To provide a time recorder which prevents unauthorized data leakage.

A time recorder 10 for outputting punch time data to a connected USB memory 100 is provided with: a control part 25 which authenticates whether the USB memory 100 is a legitimate device to receive the punch time data or not and determines whether to output the punch time data or not on the basis of the authentication result. The control part 25 performs authentication on the basis of authentication data stored in the USB memory 100. The control part 25 performs authentication on the basis of collation between identification data of the time recorder and identification data included in the authentication data stored in the external device.