To provide a device with a lock which has good operability and can enhance accuracy of determination by effectively shutting off disturbance light.

A device with a lock includes a biometric authentication device 2 in which a palm or a finger is used as a body part 1 to be authenticated; and an authentication-operation-use recess 4 which is formed in a device casing 3 and which is open in the front of the device casing 3. The device with the lock operates the lock when the biometric authentication device 2 succeeds in authentication to the body part 1 to be authenticated, which is positioned by a read guide 6 disposed in a bottom wall 5 of the authentication-operation-use recess 4. In addition, a ceiling of the authentication-operation-use recess 4 is provided, in a protruding manner, with a transparent filter cover 7 having a filter function to cut off a wavelength component of radiation light to the body part 1 to be authenticated by the biometric authentication device 2.