Switch device and electronic musical instrument

A switch device comprising:

• a first rotating operation unit which is rotatably arranged in one side section of an instrument case such that a portion thereof protrudes from a top surface of the instrument case;
• a second rotating operation unit which is rotatably arranged posterior to and separated from the first rotating operation unit such that a portion thereof is exposed on a side surface side of the one side section, and positioned such that the exposed portion is rotatable in a horizontal direction by a finger of one hand other than a thumb when the protruded portion of the first rotating operation unit is rotated in an up and down direction by the thumb;
• a first attaching member having a first attaching piece for attaching the first rotating operation unit to the instrument case at a first position of the instrument case;
• and
• a second attaching member having a second attaching piece for attaching the second rotating operation unit to the instrument case at a second position of the instrument case which is different from the first position,
• wherein the first attaching piece and the second attaching piece are attached on a same plane in the instrument case.