To provide a lateral vibration preventing device applied to a writing implement of cartridge delivery type or retractable type and also to a small tool and preventing the lateral vibration of a cartridge.

An elastic unit with which a protrusion 2a bonded through an annular belt 2b and an elastic body 2c is fitted in a holder 3 and a lateral preventing device is constituted of the elastic unit together with the holder 3. The end of the protrusion 2a is fitted in a recess 1c on the side face of the cartridge 1, and the cartridge 1 is held by urging force of the elastic unit. When the cartridge 1 is delivered forward, the protrusion 2a is tilted forward to easily protrude the cartridge 1. When the force in the diameter direction is applied to the cartridge 1 in the protruded state, the strong energizing force by the protrusion 2a is applied to prevent the lateral vibration of the cartridge 1. Also the backward movement of the cartridge 1 is prevented by a pawl 2d to keep the tilting of the protrusion 2a and easily discharge the cartridge 1.