To adjust the holding gap of a controller having a holding mechanism.

In this controller 11 having the holding mechanism where a left key plate 13a for making one end of a portable telephone 22 to be allowed to abut on the top face of a controller case 12 is erected, a right key plate 13b energized by a spring 17 is also provided in a freely slidable way while separated from the left key plate 13a, and the portable telephone 22 is press- contacted and sandwiched by the left and right key plates 13a and 13b, eccentric annular bodies 22 formed by making an inner circumferential surface eccentric to an outer circumferential surface are attached to the outer side faces of the left and right key plates 13a and 13b respectively in a freely attachable and detachable way, and the holding gap of the portable telephone 22 between the eccentric annular bodies 22 is changed by changing the mounting directions of the eccentric annular bodies 22.