Underwater drysuit

An underwater drysuit, comprising a body covering/uncovering opening part that is provided extending from one of shoulder parts to the other one of the shoulder parts on the top of arms across an area of a chest part of a drysuit main body in a chest width direction, said opening part being provided with a waterproof zipper device opening/closing defining said opening part, wherein

• said waterproof zipper device is configured in the shape of a horizontal line in said chest width direction to have a dual structure with a first waterproof zipper and a second zipper located above said first waterproof zipper in an inward/outward direction of said drysuit main body, wherein said first waterproof zipper has teeth and a slider, said teeth facing each other are provided along inner rims of two strips of elastic, waterproof tape, said slider adapted to bring into engagement said teeth with each other by the movement thereof;
• said first waterproof zipper is joined to a rear fabric of said drysuit main body and defines a main opening of said opening part;
• said second zipper is longer than said first waterproof zipper, is joined to a front fabric of said drysuit, defines a first sub-opening larger than said main opening above said main opening, and is provided in an arrangement relationship where said second zipper entirely or partially overlaps with said first waterproof zipper so as to press said first waterproof zipper from above combined with said front fabric of the drysuit, when a user wears said drysuit and closes said second zipper;
• and
• a reinforcing material that includes an open angle suppressing part, which is joined to said rear fabric along with both two strips of elastic, waterproof tape of said first waterproof zipper along outer circumferences of each said tape, from a rear side of said first waterproof zipper, and suppresses an open angle between said tapes to be opened by a slider of said first waterproof zipper, when said slider is moved to a position of a first lower end, which is a largest opening position of said first waterproof zipper, wherein this position is referred to as the first lower end position, and is then stopped at this lower end position.