your switch that tells the car that the brake is off is defective
it has a sticky handbrake switch
The handbrake light is also the 'low fluid' warning light. It is connected to the handbrake as that ensures that it is checked every time you use the handbrake. If it remains on all the time, then check the brake fluid and top up if required. If the fluid is ok then it is probably the switch on the lever and is adjustable.
Because you probably still have your handbrake on. If not, than you need to see the car-doctor.
usually a sticky switch on handbrake, had any welding recently ?, worn shoes ?
handbrake light
it means your handbrake is on
Either the switch (on the handbrake) is sticking or you have a short circuit, usually caused by corroded wires or connections.
Either your handbrake switch is broken and will not turn off or you have low brake fluid.
Release the handbrake
If the handbrake is not engaged, and the warning light is coming on, it may mean that there are components in the braking system that require maintanence. Or, it could mean that the master cylinder is low on brake fluid.
it means that the handbrake is on
You're brake fluid level may be low. A low level could be caused by a leak, or you're front brakes are almost worn out.