The invention relates to a disinfection method for use in cleaning. The invention is characterized in that hydrogen peroxide (H2O2) is drained / transferred from one or more tanks (16) by liquid pressure caused by one or more pumps or gravity through one or more drain members (6) to one or more drain devices (5), which drain device (5) hydrogen peroxide to one or more evaporation surfaces (4ea) of the evaporator (4e) of the heating / heating device (4), the evaporation surface (4ea) being at an evaporation angle (4ej) of 1 to 30 degrees such that the end of the drain device (5) spreads by gravity to the evaporator (4e), where hydrogen peroxide (H2O2) is converted to hydrogen peroxide gas by heating the heating device (4), disinfection is carried out with hydrogen peroxide gas. The invention also relates to a disinfection device for use in cleaning. The invention is characterized in that in the disinfection device body (1) with one or more drainage devices (5), by which drainage device (5) hydrogen peroxide can be drained to one or more evaporation surfaces (4e) of the evaporator (4e) , which evaporation surface (4ea) is at an evaporation angle (4ej) of 1 to 30 degrees so that the end of the drain device (5) is higher, whereby hydrogen peroxide spreads by gravity to the evaporation member (4e).Keksinnön kohteena desinfiointimenetelmä, käytettäväksi puhdistukseen. Keksinnölle on tunnusomaista se, että vetyperoksidi (H2O2) valutetaan/siirretään yhdestä tai useammasta säiliöstä (16) yhden tai useamman pumpun tai painovoiman aiheuttamalla nestepaineella yhden tai useamman valutuselimen (6) kautta yhdelle tai useammalle valutuslaitteelle (5), joka valutuslaite (5) valuttaa vetyperoksidin yhdelle tai useammalle lämmitys- /kuumennuslaitteen (4) yhdelle tai useammalle haihdutuselimen (4e) haihdutusyläpinnalle (4ea), haihdutusyläpinta (4ea) on 1 — 30 asteen haihdutuskulmassa (4ej) siten, että valutuslaitteen (5) puoleinen pää on korkeammalla, jolloin vetyperoksidi leviää pain
