A suction head of an electronic part mounting machine for firmly holding an electronic part to place it accurately in position on a printed wiring board. In this mounting machine, an inner end portion of a through bore (27) formed in the central portion of a suction nozzle (24) having at its free end a surface (33) for contact with an electronic part (10) is connected to a vacuum generator. An elastic ring (32) is fitted firmly around a free end portion of the suction nozzle (24) so that the ring (32) surrounds the circumference of the through bore (27) and projects slightly from the contact surface (33). A projecting pin (28), in which a suction portion (38) communicating with the through bore (27) is formed, is slidably fitted in the through bore (27) from a free end portion thereof so that a free end portion of the pin (28) can project from and retract in the inner side of the contact surface (33) by a predetermined length. A spring (31) urges the projecting pin (28) in the direction in which the free end portion of the pin (28) projects from the contact surface (33).