In building demolition work, major dust-generating activities are blasting concrete and rock. The aim of this study was to find the characteristic of particle size of dusts which were generated during building demolition work using explosion. The DustMate of the Turnkey-Instruments Ltd. was used for particulate size-selective sampling of the four sites. TSP(Total Suspended Particle), PM10(Particle Matter $10{mu}m$), PM2.5(Particle Matter $2.5{mu}m$), and PM1.0(Particle Matter $1.0{mu}m$) were measured during building demolition work using explosion. The large particulate (higher than the diameter $10{mu}m$) showed to be higher than 50%. The particulate ranged from $10{mu}m;to;2.5{mu}m$ showed about 30-40%. PM2.5 was not scarcely detected in the samples collected for building demolition work using explosion. We conclude that the dust generated during building demolition work using explosion has not most respirable particulate.