Vibrational frequency adjustment device and water flow type oral cavity cleaning device using same

A vibrational frequency adjustment device, comprising:

• a first conversion device that includes an input-side rotational member, an output-side rotational member, and a one-way clutch transferring only a rotational motion of the input-side rotational member in one direction to the output-side rotational member, the one-way clutch allows the input-side rotational member to make a reciprocating rotational motion by a set angle by a reciprocating linear motion of a first shaft member, thereby to transfer only a forward motion or a backward motion of the input-side rotational member to the output-side rotational member via the one-way clutch and rotate the output-side rotational member by each specific angle;
• and
• a second conversion device that converts the rotational motion of the output-side rotational member into a reciprocating linear motion of a second shaft member, the second conversion device including a first gear formed at an outer peripheral part of the output-side rotational member, a second gear engaging with first gear, and an eccentric cam allowing the second shaft member to make the reciprocating linear motion is arranged at the second gear.