Why number of zeroes in bitcoin hash is increasing?

To find a valid block the hash of the blockheader must be below the target, the hash is Hex number, everytime the difficulty is higher, the target is lower, so the number of zeroes will increase

For exemple this 32 bit number 0x00000100 contains five zeroes, if i want a number lower then this, it will contain 6 zeroes in this case: 0x000000ff

So the number of zeroes increase everytime the target is lower