To hold a notebook personal computer or peripheral equipment to a monitor device.

This holding device consists of a mount 12 formed so as to surround a monitor device 11 and a pair of holding members 13 attached to the mount 12. Holes 14 (141 to 14n) to be engaged which are formed in a lower part and holes 15 (151 to 15n) to be engaged which are formed in an upper part are provided on the left and right sides of the mount 12. The engaging nails 13d of the pair of members 13 are inserted into optional positions of the holes 14 (141 to 14n) in accordance with the horizontal width dimension of a notebook personal computer to be held. The notebook personal computer is held by the pair of members 13 locked on the side of the mount 12 attached so as to cover a monitor device 11 in a vertical state.