| 摘要 |
A keyboard (40) includes a base (410), and plural keys (41) arranged on the base (410), wherein at least a part of the plural keys (41) are arranged in plural steps in a depth direction of the keyboard (40), in the shape of a sector in such a manner that the keys closer to a central portion in a width direction of the keyboard (40) are arranged backward whereas the keys closer to both end portions in the width direction of the keyboard (40) are arranged forward. |
