A probe unit includes: first contact probes each coming into contact with a target electrode on one end side in a longitudinal direction; a second contact probe connected to an external ground; a signal pipe disposed around each first contact probes; a ground member provided around each signal pipe and configured to form an air layer with the signal pipe; a probe holder including a plate-shaped first and second members; a first wiring part provided at least on a front surface of the first member and electrically connected to the second contact probe; a second wiring part provided at least on a front surface of the second member and electrically connected to the second contact probe; a first conductive unit configured to electrically connect the first wiring part and the ground member; and a second conductive unit configured to electrically connect the second wiring part and the ground member.