An adjustable collimator (20), treatment heads (10, 10), and a radiation therapy device (100). The adjustable collimator (20) comprises a first body (21) and at least two groups of collimating apertures (22, 23, 24) provided on the first body (21). Each group of collimating apertures (22, 23, 24) comprises at least two first collimating apertures (211), the first collimating apertures (211) penetrating through opposite sides of the first body (21) the center lines of respective first collimating apertures (211) of a same group of collimating apertures (22, 23, 24) converge at a same convergent point on one side of the first body (21) the center lines of respective first collimating apertures (211) of different groups of collimating apertures (22, 23, 24) converge at different convergent points (a, b, c) on one side of the first body (21) and the distances (d1, d2, d3) from different convergent points (a, b, c) to the first body (21) are different. The adjustable collimator (20) is applicable to radiation therapy, and resolves the problem that the existing treatment heads (10, 10) cannot be used for head therapy and body therapy at the same time.La présente invention concerne un collimateur réglable (20), des têtes de traitement (10, 10) et un dispositif de radiothérapie (100). Le collimateur réglable (20) comprend un premier corps (21) et au moins deux groupes douvertures de collimation (22, 23, 24) disposés sur le premier corps (21). Chaque groupe douvertures de collimation (22, 23, 24) comprend au moins deux premières ouvertures de collimation (211), les premières ouvertures de collimation (211) pénétrant à travers des côtés opposés du premier corps (21) les lignes centrales de premières ouvertures de collimation respectives (211) dun même groupe douvertures de collimation (22, 23, 24) convergent au niveau dun même point convergent sur un côté du premier corps (21) les lignes centrales des premières ouvertures de collimation respectives (211) de différents group
