To provide a pull string operating device capable of adjusting the length of a pull string of a switching arrangement for a luminaire according to its use, simply and safely operable even by a child, inexpensive because of its simple structure, and attractive in its appearance.

In this pull string operating device, a pulley mechanism formed by combining a pull string with a stationary pulley and a movable pulley is used, the length of the pull string between the knob part and the stationary pulley can be increased by several times of the original length by using a plurality of movable pulleys. Thereby, since a sufficient length can be given to the string, a user can obtain a string with a sufficient length by which operation for lighting and putting out lights is possible after the user is tucked in a bed.