A scroll fluid machine comprising: a first scroll member having a first end plate on which a spiral first wall is provided; a second scroll member having a second end plate on which a spiral second wall is provided, the second end plate being disposed to face the first end plate and the second wall meshing with the first wall such that the second scroll member performs a revolution orbiting movement relative to the first scroll member; a tip seal which is installed in a groove portion formed on a tooth tip of each of the first wall and the second wall and is formed of a resin, the tip seal comprising: an inclined portion which is installed in the groove portion of a wall inclined portion (3b1) of the first wall, wherein the height of the wall inclined portion (3b1) is continuously changed in a spiral direction; and a flat portion which is installed in the groove portion of a wall flat portion (3b2, 3b3) of the first wall whose height is constant in the spiral direction and is adjacent to the inclined portion, characterized in that a concave portion is formed on a surface of the tip seal at a position away from a connection position between the flat portion and the inclined portion by twice or more width of the flat portion, the concave portion being recessed from the surface of the tip seal. a first scroll member having a first end plate on which a spiral first wall is provided; a second scroll member having a second end plate on which a spiral second wall is provided, the second end plate being disposed to face the first end plate and the second wall meshing with the first wall such that the second scroll member performs a revolution orbiting movement relative to the first scroll member; a tip seal which is installed in a groove portion formed on a tooth tip of each of the first wall and the second wall and is formed of a resin, the tip seal comprising: an inclined portion which is installed in the groove portion of a wall inclined portion (3b1) of the first wall, wherein the height of the wall inclined portion (3b1) is continuously changed in a spiral direction; and a flat portion which is installed in the groove portion of a wall flat portion (3b2, 3b3) of the first wall whose height is constant in the spiral direction and is adjacent to the inclined portion, characterized in that a concave portion is formed on a surface of the tip seal at a position away from a connection position between the flat portion and the inclined portion by twice or more width of the flat portion, the concave portion being recessed from the surface of the tip seal. an inclined portion which is installed in the groove portion of a wall inclined portion (3b1) of the first wall, wherein the height of the wall inclined portion (3b1) is continuously changed in a spiral direction; and a flat portion which is installed in the groove portion of a wall flat portion (3b2, 3b3) of the first wall whose height is constant in the spiral direction and is adjacent to the inclined portion, characterized in that a concave portion is formed on a surface of the tip seal at a position away from a connection position between the flat portion and the inclined portion by twice or more width of the flat portion, the concave portion being recessed from the surface of the tip seal.