A stapling operation can be performed with a comparatively small force. The stapler includes a base frame with a support element, and an operation frame pivotally attached to the support element through a main shaft. A staple pressure lower plate is disposed at the operation frame and drives staples stored in a staple magazine upon rotation of the operation frame. The stapler further includes a handle frame at an upper part of the operation frame pivotally attached to the support element such that a rear end part of the operation frame is located above the main shaft. An intermediate element is pivotally attached at one end to the handle frame. The other end of the intermediate element is pivotally attached to the operation frame.
