There is provided a medical stapler allowing an easy and secure connection of a magazine and a housing during assembly. A medical stapler 10 according to the present invention includes a magazine 2 that comprises therewithin staples 4, a rail 5 for aligning the staples 4, and a mechanism for punching out staples a lever 3 for actuating the mechanism for punching out the staples and a housing 1 for enclosing and connecting the magazine and the lever. An inner surface of the housing includes a linear positioning portion continuing from an opening of the housing, and a latching portion for latching the magazine, a surface of the magazine tangent to the inner surface of the housing includes a positioning portion in accordance with form of the positioning portion of the housing, and a latching portion in accordance with form of the latching portion of the housing, and combining the positioning portion of the housing and the positioning portion of the magazine, and fitting the latching portion of the housing and the latching portion of the magazine connect the housing and the magazine.