Bi-functional roller skate

A simply structured bi-functional roller skate has a pair of shoe embodiments. Each shoe embodiment is provided with a front securing seat which is a tubular device with a forwardly extended board, and a rear securing seat which is a tubular device with a backwardly extended board. Both the front and rear securing seats are embedded at the front end and the rear end of each shoe embodiment respectively. Each tubular device of the front and rear securing seats is in alignment with an engagement hole so as to permit a first and a second wheel axle each having a proper length to be led therethrough at the front and rear end of a shoe embodiment. Each wheel axle has a knob-ended locking screw at one end and an internally threaded section at the other end so as to permit the knob ended locking screw to be secured to the end of each wheel axle after roller wheels are mounted to the wheel axles respectively. The brake block has a threaded rod so as to make the brake block engage internally threaded holes defined at the front and rear securing seats respectively.