The present invention provides a board supporting mechanism and a board supporting method eliminating an adjustment of a support height of a support pin upon position-changing of the support pin in accordance with a change in model of a circuit board, as well as a component mounting apparatus and a component mounting method. A single or a plurality of support pin(s) (42) having one end(s) brought into contact with a bottom face of a circuit board (14) to support the bottom face of the circuit board (14) and the other end(s) brought into contact with a surface of a support table (27) for raising/lowering the support pin(s) (42) is or are held in a direction substantially perpendicular to the surface of the support table (27). The one end(s) of the support pin(s) (42) held in the direction substantially perpendicular to the surface of the support table (27) is or are brought into contact with the bottom face of the circuit board (14); thus, the support pin(s) (42) support(s) the circuit board (14).