こちらのコードを参考に
private void Form1_Load(object sender, EventArgs e) { this.MouseWheel += new MouseEventHandler(Form1_MouseWheel); } void Form1_MouseWheel(object sender, MouseEventArgs e) { if((this.VerticalScroll.Maximum - this.VerticalScroll.LargeChange) - this.VerticalScroll.Value < 0) { // 最下部 }