An instruction system (100D, 100E) comprising a target device (20, 30, 40), a master device (20D, 20E), and an instruction device (10D, 10E) configured to communicate with the master device (20D, 20E), the instruction device (10D, 10E) comprising: a first communication unit configured to receive a device ID and a reception strength included in a beacon outputted from the target device (20, 30, 40), by using a first communication means; and a second communication unit configured to send the received device ID and reception strength of the target device (20, 30, 40), by using a second communication means being different from the first communication means, and the master device (20D, 20E) comprising: a communication unit configured to receive information from the instruction device (10D, 10E), by using the second communication means; a detection unit configured to detect a space in which the instruction device (10D, 10E) exists; a storage unit configured to store association information including information indicating that the space and a target device (20, 30, 40) are associated with each other; a specifying unit (21D, 21E) configured to specify the target device (20, 30, 40) associated with the detected space by referring to the association information; and an output unit configured to output an instruction signal corresponding to the specified target device (20, 30, 40) in accordance with an operation by an operator characterized in that the detection unit is configured to detect a device ID included in a beacon having a maximum strength, and the specifying unit (21D, 21E) is configured to specify the space by referencing to the detected device ID and the association information. a first communication unit configured to receive a device ID and a reception strength included in a beacon outputted from the target device (20, 30, 40), by using a first communication means; and a second communication unit configured to send the received device ID and reception strength of the target device (20, 30, 40), by using a second communication means being different from the first communication means, and the master device (20D, 20E) comprising: a communication unit configured to receive information from the instruction device (10D, 10E), by using the second communication means; a detection unit configured to detect a space in which the instruction device (10D, 10E) exists; a storage unit configured to store association information including information indicating that the space and a target device (20, 30, 40) are associated with each other; a specifying unit (21D, 21E) configured to specify the target device (20, 30, 40) associated with the detected space by referring to the association information; and an output unit configured to output an instruction signal corresponding to the specified target device (20, 30, 40) in accordance with an operation by an operator characterized in that the detection unit is configured to detect a device ID included in a beacon having a maximum strength, and the specifying unit (21D, 21E) is configured to specify the space by referencing to the detected device ID and the association information. a communication unit configured to receive information from the instruction device (10D, 10E), by using the second communication means; a detection unit configured to detect a space in which the instruction device (10D, 10E) exists; a storage unit configured to store association information including information indicating that the space and a target device (20, 30, 40) are associated with each other; a specifying unit (21D, 21E) configured to specify the target device (20, 30, 40) associated with the detected space by referring to the association information; and an output unit configured to output an instruction signal corresponding to the specified target device (20, 30, 40) in accordance with an operation by an operator characterized in that the detection unit is configured to detect a device ID included in a beacon having a maximum strength, and the specifying unit (21D, 21E) is configured to specify the space by referencing to the detected device ID and the association information.