The problem of confinememnt is still to be understood from the first physical principles. One possible solution to this problem was suggested long ago by G. t'Hooft[1]. He suggested that confinement is driven by U(1) degrees of freedom, magnetic monopoles. Condensate of magnetic monopoles confines (chromo-) electric charges in the same way as condensate of Cooper pairs in plain superconductor confines magnetic monopoles through the formation of flux tube. To deal with monopoles we have to extract relevant U(1) degrees of freedom, i.e. make projection SU(2)~U(1) . The theory can be rewritten in terms of U(1) gauge fields with some (very complicated and non-local) action. In Monte-Carlo simulation we automatically obtain the field distributed according to this effective action averaging through ensemble of SU(2) fields. From a technical point of view we fix SU(2) gauge leaving one degree of freedom unfixed. We used in our simulation so called maximal abelian projection. In continuum this gauge is imposed by condition c9~,A~ + 3 3 z[A~,cr , A~,] -0 and in lattice we make the quantity R ~ t r ( U i , c~3U+a 3) maximized (for details see[2, 3]). After projection we extract monopole lines from remaining U(1) fields in a standard way[6]. It is well known that in confinement phase there are many monopoles and they come in big clusters filling out all space. On the other hand, in deconfinement phase monopoles are rare and well separated. 2. M o n o p o l e s C r e a t i o n O p e r a t o r in U(1 ) G a u g e T h e o r y