A medical laser apparatus suitable for medical treatment, which is capable of obtaining a plurality of visible laser beams each having a different wavelength, but which has an inexpensive structure.A medical laser apparatus capable of selectively irradiating a plurality of visible laser beams each having a different wavelength onto an affected part, comprises: a fiber laser source unit including an excitation light source, a plurality of fiber lasers for oscillating, by means of excitation light from the excitation light source, a plurality of infrared fundamental beams each having a different wavelength and a first optical switch having an input portion and a plurality of output portions for selectively switching a transmission path of the excitation light from the excitation light source to one of the fiber lasers, the fiber laser source unit being capable of selectively oscillating the fundamental beams; and a plurality of wavelength conversion elements for wavelength-converting the fundamental beams, from the fiber laser source unit, to a plurality of visible second harmonic beams.