In the present study, we have experimentally investigated an upward turbulent bubbly pipe flow focusing on the scalewise modification of the turbulent structures of the bubbly flow at ReD = 5300 (D: pipe diameter), which were measured at three vertical positions from the pipe inlet, covering developing and fully-developed regimes. The void fraction was varied from 0.2 to 1.8%. Two-phase PIV technique was used to measure the gas- and liquid-phase statistics simultaneously. To breakdown the two-phase turbulence structure according to the length-scale, we apply DWT (discrete wavelet transform) to the measured two-phase flow fields. For the single-phase turbulent flow, for all the decomposed length scales, the corresponding turbulence increases from the pipe center to the wall region, while the turbulence at largest length scale (i.e., pipe size) has the most dominant contribution. With bubbles, the turbulence at all decomposed scales increase compared to those of single-phase flow. However, the contribution of largest length scale decreases substantially but the turbulence at the second largest scale (i.e., bubble wake) dominates.