Abstract: An ergonomic computer mouse designed for the left hand, has a palm operated inputting device that alleviates the strain placed on a right hand and right hand's fingers. The device is motionless and does not contain a sensor for positioning the cursor, as with an ordinary mouse, and is operated by the user's left palm for selection functions such as clicking and double clicking operations. The user uses the ordinary mouse in his right hand only for positioning the cursor. The mouse has a big button, ergonomically shaped to fit the user's hand in a naturally relaxed position. Operations as “click” and “double click” are fulfilled by the palm of the left hand: a slight shifting of user's palm generates clicks and double-clicks, where the user clicks only once to generate a double click.