Force-adjustable staple gun

A force-adjustable staple gun, comprising:

• a case unit having an accommodation space therein;
• a staple-strike piece disposed in said accommodation space and movable in a top-bottom direction;
• a handle unit pivotably mounted to said case unit;
• a force storage unit disposed in said accommodation space, operable to resiliently bias said staple-strike piece to move in the top-bottom direction, and having an annular portion that defines an inner hole, a lever arm that is connected to one end of said annular portion, and a driver arm that is connected to another end of said annular portion, said lever arm being operable to be urged by said handle unit for said driver arm to resiliently move;
• a resilient unit disposed in said accommodation space and operable to resiliently bias said handle unit;
• and
• a force adjustment unit mounted to said case unit, and including a driver axle that is pivotably mounted to said case unit and that extends through said inner hole, and an operation member that is operable to urge said driver axle to pivot relative to said case unit, said driver axle extending along a central line, and having a first support surface that is disposed around the central line, and a second support surface that is disposed around the central line and that is located on a side of said first support surface, a first distance between said first support surface and the central line being greater than a second distance between said second support surface and the central line.