Device

A stapler, comprising:

• a first planar member being a cam shaped in a plate, the first planar member having a first surface which is a cam surface;
• and
• a second member having a second surface that forms an outer surface and is partially or wholly in contact with the first surface in a plate thickness direction of the first planar member, the second member being a cam follower,
• wherein the first member and the second member are configured to operate relatively,
• wherein a front surface of front and back surfaces of the first planar member is provided with a flow path of a lubricant connecting the first surface and configured by a concave groove that does not penetrate to the back surface,
• wherein one end of the flow path is provided with an opening that opens toward the first surface and recessed from the front surface,
• wherein an other end of the flow path communicates with an accommodating portion for the lubricant, and
• wherein the opening is provided on a downstream side of a changing point of the first surface that changes in a direction in which a distance from a portion in which the cam and the cam follower come into contact with each other to a shaft for the first planar member increases.