Portable flashlight for underwater use, which flashlight has a waterproof casing, a rechargeable battery arranged within it, a light source, as well as at least one charging connection (16, 16p, 16n) arranged on the external surface of the casing and electrically isolated from the casing, and - a first electric circuit is provided for ensuring electric connection between the rechargeable battery and the at least one charging connection, and - a second electric circuit is provided for ensuring electric connection between the rechargeable battery and the light source characterised by that a first control circuit is provided between the two contacts (16p', 16n') of the at least one charging connection and a second control circuit is provided between the two poles of the rechargeable battery, and by that the flashlight comprises a) a charging switching unit having a first magnetic switch controlled by a first magnet located outside the casing configured to break the first control circuit in a first position and close it in a second position, which first magnet switches the first magnetic switch into its second position, b) an operating switching unit having a second magnetic switch controlled by a second magnet located outside the casing configured to break the second control circuit in a first position and close it in a second position, which second magnet switches the second magnetic switch into its second position, wherein the charging switching unit has: - a first switch connected into the first electric circuit configured to break the first circuit in an open position and close the first circuit in a closed position, - a first auxiliary switch connected into the second control circuit, adapted to break the second control circuit in an open position, and close it in a closed position and - an electromagnet connected into the first control circuit, which electromagnet is adapted to switch the first switch to the closed position and the first auxiliary switch to the open position when the first magnetic switch is in its second position and the second magnetic switch is in its first position, and wherein the operating switching unit has: - a second switch connected into the second electric circuit adapted to break the second circuit in an open position and close it in a closed position, - a second auxiliary switch connected into the first control circuit adapted to break the first control circuit in an open position and close it in a closed position and - an electromagnet connected into the second control circuit, which electromagnet is adapted to switch the second switch to the closed position and the second auxiliary switch to the open position when the second magnetic switch is in its second position and the first magnetic switch is in its first position. - a first electric circuit is provided for ensuring electric connection between the rechargeable battery and the at least one charging connection, and - a second electric circuit is provided for ensuring electric connection between the rechargeable battery and the light source a) a charging switching unit having a first magnetic switch controlled by a first magnet located outside the casing configured to break the first control circuit in a first position and close it in a second position, which first magnet switches the first magnetic switch into its second position, b) an operating switching unit having a second magnetic switch controlled by a second magnet located outside the casing configured to break the second control circuit in a first position and close it in a second position, which second magnet switches the second magnetic switch into its second position, - a first switch connected into the first electric circuit configured to break the first circuit in an open position and close the first circuit in a closed position, - a first auxiliary switch connected into the second control circuit, adapted to break the second control circuit in an open position, and close it in a closed position and - an electromagnet connected into the first control circuit, which electromagnet is adapted to switch the first switch to the closed position and the first auxiliary switch to the open position when the first magnetic switch is in its second position and the second magnetic switch is in its first position, - a second switch connected into the second electric circuit adapted to break the second circuit in an open position and close it in a closed position, - a second auxiliary switch connected into the first control circuit adapted to break the first control circuit in an open position and close it in a closed position and - an electromagnet connected into the second control circuit, which electromagnet is adapted to switch the second switch to the closed position and the second auxiliary switch to the open position when the second magnetic switch is in its second position and the first magnetic switch is in its first position.