A controlled advancement laser ablation device is provided for precise ablation of body matter. The laser ablation device includes a laser energy transmission mechanism such as, e.g. a fiber optic fiber mounted for controlled translational longitudinal movement relative to a housing structure. A laser energy generator is optically connected to the laser energy transmission mechanism. A controlled advancement mechanism is provided in engagement with the laser energy transmission mechanism for advancing the mechanism through the housing structure at a controlled rated coordinated with the laser energy generator output to ablate body tissue. Controlled advancement mechanisms include constant and/or variable rate springs, motors, and other mechanisms which can be coordinated with the laser energy generator to advance the laser energy transmission mechanism as the targeted substance is ablated. The device is particularly suitable for use in transmyocardial revascularization (TMR) and angioplasty procedures.