To provide a pedal reaction force applying apparatus which is easy and inexpensive to manufacture and which is capable of obtaining a pedal reaction force which is close to that of a conventional
brake booster. A compression
coil spring 22 is compressively deformed upon depression of a pedal member 16, whereby the pedal reaction force is applied to the pedal member 16. The pedal reaction force can be suitably established depending upon amount of pivot motion of a
cam member 20 caused by a transmission mechanism 26 as a result of the depression of the pedal member 16, or depending upon projection amount and projection shape of a lobe portion 34 of the
cam member 20. Further, the
cam member 20 is mechanically pivoted by the transmission mechanism 26 upon depression of the pedal member 16, and the number of the compression
coil spring 22 to be provided in the apparatus may be one. Therefore, the apparatus can be constructed more inexpensively than an apparatus in which a desired reaction characteristic is established by rotating the cam member 20 with an
electric motor, or in which a plurality of spring members are used. Further, the apparatus can be compact in construction, and can be installed in the bracket 12 which is located in a front side of a driver's seat, with a high degree of freedom in designing the arrangement of the apparatus.