To provide an injection needle safety disposal device which is small, lightweight and suitable for home use.

When a float (6) is pushed by the operation of an operator, by which an injection needle (N) is inserted to the gap of electrode bars (10 and 20), and linearly moved, the linear movement is changed into a rotary movement and the electrode bars (10 and 20) are rotated. Therefore a motor for rotating the electrode bar (10 and 20) is omitted and a space to be occupied with the motor or a rotation transmitting mechanism is not required. Power consumption by the motor is eliminated so that the capacity of a battery can be reduced.