To make operation sure and to attain price down by using a valve mandril seal to be used for an internal combustion engine known itself as a seal element concerning a sewing machine with which a needlebar driven so as to be vertically moved is sealed to a housing by the seal element.

At the front end of the arm shaft of the sewing machine, one needlebar 5 and one presser bar 6 are arranged through a crank driving part 9 so as to be vertically driven, and the respective bars 5 and 6 are extended outside through bearing bushes 3 and 3a fixed at the lower part of a housing 1. Then, a loop-shaped step part is formed at its upper end where the bearing bush 3 is protruded into the housing 1 and at this step part, a valve mandril seal 10 is attached so that a seal lip 8 at the top end can be tightly adhered to the needlebar 5. Concerning this valve mandril seal 10, a helical tension spring ring 11 to apply radial force for improving its sealing strength is fitted to the outer peripheral section of the seal lip 8.