A tonearm unit used in a playback device configured to play a phonograph record, the tonearm unit comprising: an arm member having a tip to which a cartridge is attached; and a raising and lowering mechanism configured to raise and lower the arm member with respect to the phonograph record along a predetermined axis, wherein the raising and lowering mechanism includes: a supporting member configured to support the arm member; a rotating member provided to be rotatable about the predetermined axis with respect to the supporting member; characterized in that the raising and lowering mechanism further includes: a first guide portion on the supporting member, the first guide portion extending in a circular arc shape by tilting up from a first guide peak portion to a first guide valley portion along a rotation direction of the rotating member; and a second guide portion on the rotating member, the second guide portion facing the first guide portion and extending in a circular arc shape by tilting up from a second guide valley portion to a second guide peak portion along the rotation direction, and when the rotating member is configured to rotate with respect to the supporting member, the supporting member is configured to be raised and lowered with respect to the rotating member as a result of the second guide portion sliding along the first guide portion. an arm member having a tip to which a cartridge is attached; and a raising and lowering mechanism configured to raise and lower the arm member with respect to the phonograph record along a predetermined axis, wherein the raising and lowering mechanism includes: a supporting member configured to support the arm member; a rotating member provided to be rotatable about the predetermined axis with respect to the supporting member; characterized in that the raising and lowering mechanism further includes: a first guide portion on the supporting member, the first guide portion extending in a circular arc shape by tilting up from a first guide peak portion to a first guide valley portion along a rotation direction of the rotating member; and a second guide portion on the rotating member, the second guide portion facing the first guide portion and extending in a circular arc shape by tilting up from a second guide valley portion to a second guide peak portion along the rotation direction, and a supporting member configured to support the arm member; a rotating member provided to be rotatable about the predetermined axis with respect to the supporting member; characterized in that the raising and lowering mechanism further includes: a first guide portion on the supporting member, the first guide portion extending in a circular arc shape by tilting up from a first guide peak portion to a first guide valley portion along a rotation direction of the rotating member; and a second guide portion on the rotating member, the second guide portion facing the first guide portion and extending in a circular arc shape by tilting up from a second guide valley portion to a second guide peak portion along the rotation direction, and when the rotating member is configured to rotate with respect to the supporting member, the supporting member is configured to be raised and lowered with respect to the rotating member as a result of the second guide portion sliding along the first guide portion.