A vibrational frequency adjustment device comprises, as a vibrational frequency adjustment means (22): a first conversion means (40) which is provided with an input-side rotating member (41), an output-side rotating member (42), and a one-way clutch (44) for transmitting only the rotational motion in one direction of the input-side rotating member (41) to the output-side rotating member (42) and which, by causing the input-side rotating member (41) to pivot in a reciprocating manner by a set angle by means of the reciprocating linear motion of an output shaft (10), transmits only the forward motion or the reverse motion of the input-side rotating member (41) to the output-side rotating member (42) through the one-way clutch (44) to thereby rotate the output-side rotating member (42) by a given angle； and a second conversion means (50) which converts the rotational motion of the output-side rotating member (42) into the reciprocating linear motion of a second shaft member (43).
