Device for welding profiled elements in plastic material, in particular PVC, comprising: - a base frame that supports a pair of retaining members of respective profiled elements (3; 3a, 3b; 60, 61), to engage said profiled elements (3; 3a, 3b; 60, 61) with corresponding zones to be welded (4; 62, 63) facing one another; - heating means for heating said zones to be welded (4; 62, 63) of the profiled elements (3; 3a, 3b; 60, 61), comprising at least a hot-plate heat-sealing element and mobile between an active condition wherein they are placed between said profiled elements (3; 3a, 3b; 60, 61) and a non-use condition wherein they are spaced at a distance from said profiled elements (3; 3a, 3b; 60, 61); - movement means of said retaining members, to shift the profiled elements (3; 3a, 3b; 60, 61) between a first reciprocal away direction and a second reciprocal closer direction wherein the zones to be welded (4; 62, 63) are coupled together; - removal means to make at least one groove on a peripheral edge of at least one zone to be welded (4; 62, 63); characterised in that: - said removal means are composed of removal means by milling; and - said removal means by milling comprise: - a supporting frame positioned in correspondence to said retaining members; - at least one machining tool facing a respective profiled element (3; 3a, 3b; 60, 61) to make said groove on the zone to be welded (4; 62, 63); - a motor part associated with said tool; and - a movement member of the tool, to move it between a first idle condition and a second working condition wherein it is placed between the profiled elements (3; 3a, 3b; 60, 61). - a base frame that supports a pair of retaining members of respective profiled elements (3; 3a, 3b; 60, 61), to engage said profiled elements (3; 3a, 3b; 60, 61) with corresponding zones to be welded (4; 62, 63) facing one another; - heating means for heating said zones to be welded (4; 62, 63) of the profiled elements (3; 3a, 3b; 60, 61), comprising at least a hot-plate heat-sealing element and mobile between an active condition wherein they are placed between said profiled elements (3; 3a, 3b; 60, 61) and a non-use condition wherein they are spaced at a distance from said profiled elements (3; 3a, 3b; 60, 61); - movement means of said retaining members, to shift the profiled elements (3; 3a, 3b; 60, 61) between a first reciprocal away direction and a second reciprocal closer direction wherein the zones to be welded (4; 62, 63) are coupled together; - removal means to make at least one groove on a peripheral edge of at least one zone to be welded (4; 62, 63); characterised in that: - said removal means are composed of removal means by milling; and - said removal means by milling comprise: - a supporting frame positioned in correspondence to said retaining members; - at least one machining tool facing a respective profiled element (3; 3a, 3b; 60, 61) to make said groove on the zone to be welded (4; 62, 63); - a motor part associated with said tool; and - a movement member of the tool, to move it between a first idle condition and a second working condition wherein it is placed between the profiled elements (3; 3a, 3b; 60, 61). - a supporting frame positioned in correspondence to said retaining members; - at least one machining tool facing a respective profiled element (3; 3a, 3b; 60, 61) to make said groove on the zone to be welded (4; 62, 63); - a motor part associated with said tool; and - a movement member of the tool, to move it between a first idle condition and a second working condition wherein it is placed between the profiled elements (3; 3a, 3b; 60, 61).