A variable collapsible pen especially for dogs, comprising: at least one rear frame (1.1) made of a corrosion-resistant material, provided with a back and formed by stems (1.1.n, 1.1.n+1) of corrosion-resistant material, wherein each rear frame (1.1) comprises a first stem (1.1.n) fitted with a foot (1.4) at the bottom with anchoring holes and a second stem (1.1.n+1) fitted with a foot (1.4) at the bottom with anchoring holes, wherein the first stem (1.1.n) and the second stem (1.1.n+1) are interconnected at least with a top crossbeam (1.2), a center crossbeam (1.16) and a bottom crossbeam (1.3), the crossbeams (1.2, 1.16, 1.3) being made of corrosion-resistant material, wherein the first stem (1.1.n) is provided in its bottom half under the level of the center crossbeam (1. 16) at least on one side with three hinges (1.8) with which the first stem (1.1.n) is connected to a first side panel frame (2.1) filled with an opaque panel (2.9), wherein the first side panel frame (2.1) is provided on its inner side in its bottom third with a horizontal flat bar (2.3) affixed to the first side panel frame (2.1) and provided with a counterpart (2.10) of a locking mechanism (4.3), wherein the center crossbeam (1.16) is provided with at least two roof hinges (1.7), with which it is connected to a roof frame (5.1) with a roof panel (5.6) forming a canopy, wherein the roof frame (5.1) is provided with at least two locks (5.5) against unintentional folding of the canopy, and at least two first mounts (5.9) of a respective roof spring (1.10), wherein the roof springs (1.10) are connected at the respective first mounts (5.9) to the roof frame (5.1) and with respective second mounts (1.9) to the top part of the first and second stem (1.1.n, 1.1.n+1), wherein the top crossbeam (1.2) is provided with two counterparts (1.6.1) of the locks (5.5) against unintentional folding of the canopy and wherein the second stem (1.1.n+1) is provided in its bottom half under the level of the center crossbeam (1.16) at least on one side with at least three hinges (1.15) of a second side panel, with which the second stem (1.1.n+1) is connected to the second side panel frame (2.1), wherein the second side panel frame (2.1) is provided with a lock (1.6) against unintentional opening, wherein the second side panel frame (2.1) has an opaque panel (2.9) and wherein the second side panel frame (2.1) is connected via door hinges (4.7) with a door frame (4.1) with a transparent perforated door panel (4.6) provided with a locking mechanism (4.3), and wherein the second side panel frame (2.1) is provided with a counterpart (2.10) of the locking mechanism. at least one rear frame (1.1) made of a corrosion-resistant material, provided with a back and formed by stems (1.1.n, 1.1.n+1) of corrosion-resistant material, wherein each rear frame (1.1) comprises a first stem (1.1.n) fitted with a foot (1.4) at the bottom with anchoring holes and a second stem (1.1.n+1) fitted with a foot (1.4) at the bottom with anchoring holes, wherein the first stem (1.1.n) and the second stem (1.1.n+1) are interconnected at least with a top crossbeam (1.2), a center crossbeam (1.16) and a bottom crossbeam (1.3), the crossbeams (1.2, 1.16, 1.3) being made of corrosion-resistant material, wherein the first stem (1.1.n) is provided in its bottom half under the level of the center crossbeam (1. 16) at least on one side with three hinges (1.8) with which the first stem (1.1.n) is connected to a first side panel frame (2.1) filled with an opaque panel (2.9), wherein the first side panel frame (2.1) is provided on its inner side in its bottom third with a horizontal flat bar (2.3) affixed to the first side panel frame (2.1) and provided with a counterpart (2.10) of a locking mechanism (4.3), wherein the center crossbeam (1.16) is provided with at least two roof hinges (1.7), with which it is connected to a roof frame (5.1) with a roof panel (5.6) forming a canopy, wherein the roof frame (5.1) is provided with at least two locks (5.5) against unintentional folding of the canopy, and at least two first mounts (5.9) of a respective roof spring (1.10), wherein the roof springs (1.10) are connected at the respective first mounts (5.9) to the roof frame (5.1) and with respective second mounts (1.9) to the top part of the first and second stem (1.1.n, 1.1.n+1), wherein the top crossbeam (1.2) is provided with two counterparts (1.6.1) of the locks (5.5) against unintentional folding of the canopy and wherein the second stem (1.1.n+1) is provided in its bottom half under the level of the center crossbeam (1.16) at least on one side with at least three hinges (1.15) of a second side panel, with which the second stem (1.1.n+1) is connected to the second side panel frame (2.1), wherein the second side panel frame (2.1) is provided with a lock (1.6) against unintentional opening, wherein the second side panel frame (2.1) has an opaque panel (2.9) and wherein the second side panel frame (2.1) is connected via door hinges (4.7) with a door frame (4.1) with a transparent perforated door panel (4.6) provided with a locking mechanism (4.3), and wherein the second side panel frame (2.1) is provided with a counterpart (2.10) of the locking mechanism.