A brake system for a motorcycle, the brake system including a first operation element and a second operation element operated by a rider, the brake system comprising: a front-wheel braking section that includes a first friction application device for braking a front wheel of the motorcycle at least with a friction force corresponding to motion of the first operation element; a rear-wheel braking section that includes a second friction application device for braking a rear wheel of the motorcycle at least with a friction force corresponding to motion of the second operation element; and a controller that performs slip control operation for controlling slips of the front wheel and the rear wheel, wherein the front-wheel braking section further includes: a master cylinder, to which the motion of the first operation element is transmitted; a wheel cylinder that communicates with said master cylinder via a fluid path filled with a brake fluid; and a hydraulic pressure adjustment mechanism (32, 33, 36, 38, 39) that adjusts a hydraulic pressure of the brake fluid in said wheel cylinder, in the front-wheel braking section, the friction force, which is applied to the front wheel by the first friction application device, varies according to the hydraulic pressure of the brake fluid in the master cylinder during service braking and varies by control of the hydraulic pressure adjustment mechanism (32, 33, 36, 38, 39) by the controller during the slip control operation, the rear-wheel braking section further includes: a second operation element motion sensor that detects motion of the second operation element; and an actuator that is unitized with the second friction application device, and in the rear-wheel braking section, the friction force, which is applied to the rear wheel by the second friction application device, varies according to control of the actuator by the controller corresponding to a detection result of the second operation element motion sensor during the service braking and varies by the control of said actuator by said controller during the slip control operation, characterized in that the controller includes: a first control section that governs operation of the hydraulic pressure adjustment mechanism (32, 33, 36, 38, 39); and a second control section that governs operation of the actuator, the first control section is unitized with the hydraulic pressure adjustment mechanism (32, 33, 36, 38, 39), and the second control section is unitized with the second operation element motion sensor. a front-wheel braking section that includes a first friction application device for braking a front wheel of the motorcycle at least with a friction force corresponding to motion of the first operation element; a rear-wheel braking section that includes a second friction application device for braking a rear wheel of the motorcycle at least with a friction force corresponding to motion of the second operation element; and a controller that performs slip control operation for controlling slips of the front wheel and the rear wheel, wherein the front-wheel braking section further includes: a master cylinder, to which the motion of the first operation element is transmitted; a wheel cylinder that communicates with said master cylinder via a fluid path filled with a brake fluid; and a hydraulic pressure adjustment mechanism (32, 33, 36, 38, 39) that adjusts a hydraulic pressure of the brake fluid in said wheel cylinder, in the front-wheel braking section, the friction force, which is applied to the front wheel by the first friction application device, varies according to the hydraulic pressure of the brake fluid in the master cylinder during service braking and varies by control of the hydraulic pressure adjustment mechanism (32, 33, 36, 38, 39) by the controller during the slip control operation, the rear-wheel braking section further includes: a second operation element motion sensor that detects motion of the second operation element; and an actuator that is unitized with the second friction application device, and in the rear-wheel braking section, the friction force, which is applied to the rear wheel by the second friction application device, varies according to control of the actuator by the controller corresponding to a detection result of the second operation element motion sensor during the service braking and varies by the control of said actuator by said controller during the slip control operation, characterized in that the controller includes: a first control section that governs operation of the hydraulic pressure adjustment mechanism (32, 33, 36, 38, 39); and a second control section that governs operation of the actuator, the first control section is unitized with the hydraulic pressure adjustment mechanism (32, 33, 36, 38, 39), and the second control section is unitized with the second operation element motion sensor.