A sensor unit (U2, U3) attachable to an accommodation hole, the accommodation hole extending through a housing in a first direction (Z-Z') and being closed by an overlay on one side in the first direction (Z-Z'), the sensor unit (U2, U3) being attachable to the accommodation hole from the other side (Z') in the first direction (Z-Z'), the sensor unit (U2, U3) comprising: a body including a first portion and a second portion on the other side (Z') in the first direction (Z-Z') relative to the first portion, the first portion being accommodatable in the accommodation hole of the housing from the other side (Z') in the first direction (Z-Z'), the second portion being located on the other side (Z') in the first direction (Z-Z') relative to the accommodation hole with the first portion accommodated in the accommodation hole; a detection sensor provided at the body and configured to detect a contact of a detection target with the overlay from the one side in the first direction (Z-Z') with the first portion of the body accommodated in the accommodation hole; a vibration generator configured to vibrate the body and the detection sensor, with the first portion of the body accommodated in the accommodation hole, and thereby provide a tactile feedback to the detection target in contact with the overlay; a fixable part provided at the second portion of the body, the fixable part being located on the other side (Z') in the first direction (Z-Z') relative to the housing with the first portion of the body accommodated in the accommodation hole, a relay fixed to the fixable part, the relay being fixable to the housing from the other side (Z') in the first direction (Z-Z') with the first portion of the body accommodated in the accommodation hole; and a vibration damper constituted by an elastic substance and at least partly interposed between the fixable part and the relay, characterized in that the vibration damper includes a first vibration damper constituted by an elastic substance and a second vibration damper constituted by an elastic substance, and the relay includes a first abuttable portion located on the one side in the first direction (Z-Z') relative to the first vibration damper, and a second abuttable portion located on the other side (Z') in the first direction (Z-Z') relative to the second vibration damper, the first vibration damper is interposed between the fixable part and the first abuttable portion of the relay, and the second vibration damper is interposed between the fixable part and the second abuttable portion of the relay. a body including a first portion and a second portion on the other side (Z') in the first direction (Z-Z') relative to the first portion, the first portion being accommodatable in the accommodation hole of the housing from the other side (Z') in the first direction (Z-Z'), the second portion being located on the other side (Z') in the first direction (Z-Z') relative to the accommodation hole with the first portion accommodated in the accommodation hole; a detection sensor provided at the body and configured to detect a contact of a detection target with the overlay from the one side in the first direction (Z-Z') with the first portion of the body accommodated in the accommodation hole; a vibration generator configured to vibrate the body and the detection sensor, with the first portion of the body accommodated in the accommodation hole, and thereby provide a tactile feedback to the detection target in contact with the overlay; a fixable part provided at the second portion of the body, the fixable part being located on the other side (Z') in the first direction (Z-Z') relative to the housing with the first portion of the body accommodated in the accommodation hole, a relay fixed to the fixable part, the relay being fixable to the housing from the other side (Z') in the first direction (Z-Z') with the first portion of the body accommodated in the accommodation hole; and a vibration damper constituted by an elastic substance and at least partly interposed between the fixable part and the relay, characterized in that the vibration damper includes a first vibration damper constituted by an elastic substance and a second vibration damper constituted by an elastic substance, and the relay includes a first abuttable portion located on the one side in the first direction (Z-Z') relative to the first vibration damper, and a second abuttable portion located on the other side (Z') in the first direction (Z-Z') relative to the second vibration damper, the first vibration damper is interposed between the fixable part and the first abuttable portion of the relay, and the second vibration damper is interposed between the fixable part and the second abuttable portion of the relay.