A sewing machine includes a sewing machine body formed with a cassette mount, a thread cassette having a supply of thread and detachably attached to the cassette mount, and a moving speed limiting unit limiting a moving speed of the thread cassette when the thread cassette is attached to the cassette mount. The moving speed limiting unit includes a moving member capable of moving substantially together with the thread cassette in the course of movement of the thread cassette to a predetermined position in the cassette mount, a rotating member rotated by movement of the moving member, and a rotational resistance applying unit applying rotational resistance to the rotating member.