An information input/output device includes: a position input unit configured to designate a position by a user in a prescribed operation area Sd in real space; a designated position measurement unit configured to measure a designated position “rd” in the operation area Sd, which is designated by the user in the position input unit; an operation area offset amount determination unit configured to determine an offset amount “Δrv0” of an origin position “rv0” of an operation area Sv in virtual space based on the measured position “rd” in the operation area Sd; and a designated position determination unit configured to determine a designated position “rv” in virtual space which corresponds to the position in real space designated by the user through the position input unit based on the measured position “rd” in the operation area Sd, the origin position “rv0” of the operation area Sv in virtual space and the determined offset amount “Δrv0”.