A head-mounted device for mounting on the head of a user includes a first pressing member for pressing a first portion of the head from a first direction; a second pressing member for pressing a second portion of the head from a second direction that is different from the first direction; a string member that concatenates the first pressing member and the second pressing member; a structure that guides the string member so that the first and the second pressing members move in the first and the second directions, respectively, according to changes in the length of the string member; and an adjusting unit that adjusts the length of the string member.