An optical measuring system comprises a control device and an optical meter. The optical meter comprises a first case, a first controller for controlling light emitters for irradiating a patient with light and light receivers for receiving light from the patient to obtain measurement data regarding a cerebral activity, and a first transmitter and receiver for transmitting the measurement data to the control device. The control device comprises a second case removably attached to the first case, a display and input device on a surface of the second case, a second transmitter and receiver for receiving the measurement data from the optical meter, and a second controller for controlling the display and input device to display the measurement data from the optical meter. The second case can be attached on a top face of the first case when the first case is placed on a table.
