Computer mouse

A computer mouse comprising:

• a base unit;
• a button unit pivotally mounted to said base unit via a front part of said button unit, and being able to be actuated to allow a rear part of said button unit to substantially pivot in an up-down direction relative to said base unit;
• and
• a fastening unit disposed between said base unit and said button unit, and operable to position said button unit relative to said base unit;
• wherein said base unit includes a plurality of positioning sets that are substantially spaced apart from each other in the up-down direction, said fastening unit including an actuating member that is pivotally mounted to said button unit and that is operable to separably engage a selected one of said positioning sets so as to position said button unit relative to said base unit;
• and
• wherein each of said positioning sets has two slots that are spaced apart from each other in a left-right direction, said actuating member having an operating part that is pivotally mounted to said button unit, and two fastening parts that extend from said operating part, that extend away from each other and that respectively and separably engage said slots of the selected one of said positioning sets, said fastening unit further including a restoring member that is connected between said fastening parts and said button unit, said restoring member constantly providing a restoring force for said fastening parts to move toward said slots.