A stimulus imparting device comprising: at least one of a first vibration device adapted to be provided at a chair to be positioned to face to a tendon portion of musculus latissimus dorsi of a user when the user is seated on the chair for imparting a stimulus to tendon portion of musculus latissimus dorsi of the user and a second vibration device adapted to be provided at the chair to be positioned to face to a tendon portion of musculus gluteus medius of the user when the user is seated on the chair for imparting the stimulus to the tendon portion of musculus gluteus medius of the user; and a control device including a drive control portion which is configured to impart the stimulus to the user by driving at least one of the first vibration device and the second vibration device, characterized in that the control device further includes: a first judging portion which is configured to judge whether or not a suppression of generation of drowsiness of the user sitting on the chair is necessary; and a first stimulus pattern deciding portion which is configured to decide a first stimulus pattern for suppressing the generation of the drowsiness when the suppression of generation of drowsiness of the user is judged to be necessary by the first judging portion, wherein the drive control portion is configured to impart stimulus to the user by driving at least the one of the first vibration device and the second vibration device based on the first stimulus pattern decided by the first stimulus pattern deciding portion; a second judging portion which is configured to judge whether or not an elimination of drowsiness of the user sitting on the chair is necessary; and a second stimulus pattern deciding portion which is configured to decide a second stimulus pattern for eliminating the drowsiness when the elimination of drowsiness of the user is judged to be necessary by the second judging portion, wherein the drive control portion is configured to impart stimulus to the user by driving at least the one of the first vibration device and the second vibration device based on the second stimulus pattern decided by the second stimulus pattern deciding portion. at least one of a first vibration device adapted to be provided at a chair to be positioned to face to a tendon portion of musculus latissimus dorsi of a user when the user is seated on the chair for imparting a stimulus to tendon portion of musculus latissimus dorsi of the user and a second vibration device adapted to be provided at the chair to be positioned to face to a tendon portion of musculus gluteus medius of the user when the user is seated on the chair for imparting the stimulus to the tendon portion of musculus gluteus medius of the user; and a control device including a drive control portion which is configured to impart the stimulus to the user by driving at least one of the first vibration device and the second vibration device, characterized in that the control device further includes: a first judging portion which is configured to judge whether or not a suppression of generation of drowsiness of the user sitting on the chair is necessary; and a first stimulus pattern deciding portion which is configured to decide a first stimulus pattern for suppressing the generation of the drowsiness when the suppression of generation of drowsiness of the user is judged to be necessary by the first judging portion, wherein the drive control portion is configured to impart stimulus to the user by driving at least the one of the first vibration device and the second vibration device based on the first stimulus pattern decided by the first stimulus pattern deciding portion; a second judging portion which is configured to judge whether or not an elimination of drowsiness of the user sitting on the chair is necessary; and a second stimulus pattern deciding portion which is configured to decide a second stimulus pattern for eliminating the drowsiness when the elimination of drowsiness of the user is judged to be necessary by the second judging portion, wherein the drive control portion is configured to impart stimulus to the user by driving at least the one of the first vibration device and the second vibration device based on the second stimulus pattern decided by the second stimulus pattern deciding portion. a first judging portion which is configured to judge whether or not a suppression of generation of drowsiness of the user sitting on the chair is necessary; and a first stimulus pattern deciding portion which is configured to decide a first stimulus pattern for suppressing the generation of the drowsiness when the suppression of generation of drowsiness of the user is judged to be necessary by the first judging portion, wherein the drive control portion is configured to impart stimulus to the user by driving at least the one of the first vibration device and the second vibration device based on the first stimulus pattern decided by the first stimulus pattern deciding portion; a second judging portion which is configured to judge whether or not an elimination of drowsiness of the user sitting on the chair is necessary; and a second stimulus pattern deciding portion which is configured to decide a second stimulus pattern for eliminating the drowsiness when the elimination of drowsiness of the user is judged to be necessary by the second judging portion, wherein the drive control portion is configured to impart stimulus to the user by driving at least the one of the first vibration device and the second vibration device based on the second stimulus pattern decided by the second stimulus pattern deciding portion.