The present invention relates to a handcart having variable mounting boards. The present invention provides a handcart having variable mounting boards, comprising: a support frame, an upper portion of which has a handle; mounting boards which are arranged at the lower portion of the support frame, and each of which has a rail dome for enabling the mounting boards to slide in the left and right directions and enabling cargo loading/unloading operations to be easily performed; buffering means having a buffering wheel rotatably arranged at a side of each mounting board, a movable shaft which penetrates through one side of the mounting board, and a spring which covers the movable shaft so as to absorb shocks generated during the transportation of cargo; a guide assembly having a guide rail slidably coupled to the rail dome, a plurality of rack gears coupled to the rail dome, and spur gears which engage with the rack gears and which have rotatable handles; and a guide case which protects the rack gears and the spur gears from foreign substances, and which has an elongate hole for facilitating the sliding motion of the rail dome.